Introduction:
The stock stampede plastic breech does not have an air-tight bolt to barrel seal, hence the plastic bolt itself is essentially the barrel. Once the foam dart is fired out the bolt, the foam dart already starts losing power and velocity. In addition, most of the air pressure from the plunger is wasted once the foam dart leaves the bolt.
The design objective of an air-tight brass breech system is to create a 100% air-tight seal all the way from the plunger through to the barrel, thereby providing efficient air pressure delivery to propel the foam darts further.
This would result in more power within each shot, with greater firing distance and faster dart velocity.
For a Stampede brass breech to work, it requires the air-tight connection of matching brass tubes and a guide cover to ensure that all the moving parts are aligned properly.
My design is optimized to work with stefans (short length customized foam darts), although it could be adapted to use normal length foam darts, they usually wouldn't perform as accurately or consistently, and may result in much higher rates of jams.
The following guide will cover my customized version of the "Brass Breech" mod.
Credits:
My brass breech design for the Stampede is based on the excellent "PVC guide cover" design by Oxymoron at the OzNerf forum, full credit goes to him for that design.
Link to the original "Oxy's Stampede Breech" thread by Oxymoron at the OzNerf forum.
Important Note:
The "Brass Breech" mod is a more advanced mod project that should only be performed by those who are already familiar with modding the Stampede.
For new modders, please refer to my Nerf Stampede Mod Guide to get familiar with the modding basics first.
Disclaimer: Modify at your own risk. Modifications may wear out or damage your blaster. Please be careful when using hobby tools!
Lets start...
Step 1: You will need to obtain 3 different sizes of brass tubes (Brand: K&S Engineering) and a suitable PVC pipe for nesting them into.
The brass tube sizes are: 1/2", 17/32" and 9/16". All of them are 0.014" wall thickness. They are usually supplied at hobby shops in either 1 ft or 3 ft length tubes.
I use a 13mm SingaPlastics brand PVC pipe which can nest the 9/16" brass tube. This pipe will be used to create the PVC guide cover.
Note that the inner diameters (ID) of PVC pipes often tend to have variations, even within the same length of pipe, so you have to test different sections and make sure it fits the brass tubes before usage.
Its recommended to prepare and polish the brass tubes with some metal polish to remove any oxidization that may have occurred both externally and inside the tubes, this helps smoothen out the surfaces for lower friction and better fit.
As you can see, the brass tubes nest perfectly within each other and they all form an instant 100% air-tight seal. Those who have worked with brass breech systems will be very familiar with this unique characteristic. :)
Step 2:
Lets start with the PVC guide cover, this is the most essential part of the Stampede brass breech system. The guide cover ensures that the moving brass bolt chambers each foam dart into the barrel properly and consistently.
Take the PVC pipe and mount the N-Strike clip on it.
Use a marker to trace the outline of the clip's shape.
Use a Dremel with cut-off wheel to cut out the traced lines.
As the top section of the guide cover ends up being a rather thin strip of PVC (which will tend to flex too much), i cut out another shaped part from a larger 16mm SingaPlastics brand PVC pipe which is then glued on the top to further reinforce and stiffen that section.
The PVC guide cover is done!
Step 3:
Now we proceed on to the brass barrel section.
In my example, i use a 21 cm length (8+ inch) of 9/16" brass tube as the barrel. It is nested and glued into the PVC guide cover.
Use a Dremel with sanding bit to bevel the inner edges of the brass barrel, this creates a funnel design to enable smoother chambering of the foam darts and brass bolt.
I positioned the barrel and guide cover assembly to align with the internal dimensions of the Stampede, an additional PVC pipe was nested at the front of the barrel to help keep it in line with the Stampede's front casing structure piece.
The orange collar piece is also positioned and glued to the PVC guide cover to establish a fixed securing point to the blaster casing.
The brass barrel section is done!
Step 4:
Next we proceed to the brass bolt section.
Use a pipe cutter to cut away the stock plastic bolt, as shown in this photo.
To make the brass bolt parts, use a Dremel to separately cut out a set of brass tube sections in the following lengths:
1/2" brass tube: 11 cm
17/32" brass tube: 2 cm (2 x spacer sections)
9/16" brass tube : 9 cm
These are my custom tube measurements for the Stampede brass breech system.
These measurements need to be as accurate as possible. Any variations may affect the overall structure and air seal of the breech system.
Used a Dremel with sanding bit to bevel the outer edges of the brass bolt front section, this will help to further enable smoother chambering of the foam darts and brass bolt into the brass barrel.
Here is my Nested Brass Tubes Cut-Away Diagram:
Nest the assembled brass bolt into the plunger casing.
Use the strongest glue you can get to glue everything together. I use "Selleys Super Strength" 2-part slow-curing epoxy glue (curing time of 3 days!). Make sure the glue cures completely for maximum bond strength.
Note that the 1/2" brass tube acts as the air channel and helps to reduce dead space, but not too much to create an air restriction.
The 17/32" brass tube will chamber the foam dart and connect into the 9/16" brass barrel, this is what creates the 100% air seal.
The brass bolt section is done!
Step 5:
Sleeve the brass bolt into the PVC guide cover. Test the parts movement and connection with the brass barrel.
The brass bolt must be able to move smoothly within the PVC guide cover without resistance.
If there is resistance, use a Dremel with sanding bit to widen the inner diameter (ID) of the PVC guide cover until it fits.
When the 17/32" brass bolt connects into the 9/16" brass barrel, it should have a 100% air-tight seal. Test the seal by closing the breech, then manually compressing the plunger while blocking the barrel exit, there should be resistance felt in the plunger rod.
Next, install all the parts into the Stampede.
Test the parts fit and test the movement of the brass bolt. Make sure everything moves smoothly.
If there are parts which encounter resistance, either loosen or trim the fit and test again.
Assemble everything together, keep testing the movement of the parts as you assemble the blaster.
Its completed!
Here are some close-ups of the breech system:
Awesome!
Stampede Brass Breech - Demo & Test Fire Video:
Sample Test Fire Results:
PTG: Parallel-To-Ground (Shoulder height, no elevation)
ATG: Angled-To-Ground (Aimed higher, 30 degrees elevation)
Distance is measured at where the dart lands (Average of 6 darts).
Brass Breech Stampede (9kg Load Spring)
Ammo: Customized FBR foam + 1.1 gram soft silicone tip weight
PTG = 95-105 ft
ATG = 120-130 ft
Note that the test was done indoors with customized foam darts and the results are sample estimates for reference (your results may differ depending on materials and mod techniques used).
Important User Tips:
- Short length customized stefans work best with this breech system, make sure that the stefans used are in perfect condition and fit the brass barrel properly (not too narrow or not too wide). In addition, ensure that the back portions of the stefans are rounded without any excess foam sticking out which might get clipped by the brass breech when it closes. Taking care of these various factors will greatly reduce the chances of jamming.
- With the clip and trigger locks removed, do not put your fingers into the breech section when the blaster is in operation, as this can result in injuries.
- The better the foam dart fit in the brass barrel, the better the range results.
Variants:
For fans of minimized Stampedes... check out the brass breech mod done on my "SMG" Variant!
Note the extra length of PVC pipe and coupler covering the brass barrel in front, it is designed to cover the brass tube edges for safety in Nerf games. :)
Check it out in action!
Hey mate,
ReplyDeleteSome quality work as usual. Something I'll have to replicate in the near future.
I really like the reinforcing of the pvc breech, it's definitely an idea that I'll be utilising very soon.
Just curious as to the length of the darts you're using.
Cheers,
Clunk
clunk07,
DeleteThe stefans i used are made from 3cm lengths of FBR with silicone tips... so in total they work out to around 3.5cm in overall length.
Great work, I use streamline-length stefans in my blasters, so I will have to cut down your design to fit, do you reckon it would seal properly?
ReplyDeletealso this (especially with a 13 kg spring) looks to be a suitable replacement for the long-shot, now that it is going out of production, but with infinitely better ROF. Oh How I will sell miss the long-shot.
wanna-be,
DeleteWell, my design works on the concept of the 17/32" bolt section nesting into the 9/16" brass barrel, so if the gap is widened the connection tolerance would just be narrower, so there is less margin for error, especially during the chambering process.
I guess you could try adjusting the measurements and see if you can tweak it to still work consistently with normal length foam darts.
Alternatively, you could also just trim the foam darts abit shorter to better fit the breech system. Shorter foam darts also usually tend to have better accuracy. :)
Any chance you might be selling these at some point? I lack both the source and the tools to do this...
ReplyDeleteBLACKOUT,
DeleteSorry, i've no plans to mod blasters for others. :)
There's probably pretty good money there. Oh, well. Could I get a link to where you got the brass, then?
DeleteBLACKOUT,
DeleteI get my K&S brass tubes from a local RC hobby shop in Singapore, called NTC Hobby:
http://www.myrcstore.com/
I guess you can also find K&S brass tubes at most RC hobby shops and online hobby sites too. Just shop around to find them.
Hi,
ReplyDeleteCan I do that on a minimized stampede
Thnx:D
greendra1000,
DeleteYup, this mod can also be done on minimized Stampedes too, but you'll have to either shorten the barrel to fit within the minimized casing... or let the full barrel length stick out of the casing (for safety, encase the brass barrel in PVC pipe to cover the brass barrel edges). :)
Ok Thnx:D
DeleteFrom your opinion,do u think a 6 inch barrel optimal enuff for the BB stampede??
Sry if I am asking a stupid question....
Cheers:D
greendra1000,
DeleteI've not tested it with 6" barrels yet, but that barrel length should work well too... i guess you'll have to build and test with that setup to see if there is any noticeable performance difference.
DUDE you get better and better every post!
ReplyDeleteimodify,
DeleteThanks! :)
How much of range boost does this give over a stock breech and 9kg spring?
ReplyDeleteTBA,
DeleteYou can compare the range differences by referencing the data at my Stampede Mod Guide:
http://modworks.blogspot.com/2010/09/nerf-stampede-mod-guide.html
...And then SGnerf created his Brass Breech Stampede, and that was the end of the NIC. :)
ReplyDeleteI'm so jealous of the PVC you guys have in Singapore. Would it be at all possible for you to ship the PVC I would need for this mod to the US?
ReplyDeleteInterflop,
DeletePossible, just send me a message at my YouTube channel. :)
Hey sg i was wondering what is a fully modded stampede?
ReplyDeleteimodify,
DeleteIf you are referring to the basic mods for a Stampede, read my Stampede Mod Guide here:
http://modworks.blogspot.com/2010/09/nerf-stampede-mod-guide.html
so that would be a fully modded stampede?
ReplyDeleteimodify,
DeleteWell, that's what i would just term as a basic modded Stampede... i guess some modders might call their blasters "fully" modded too, depending on what mods they actually do on it.
Will the one you made fit both stefans and stock darts? It seems possible, based on the distance that the bolt travels, and the length of a streamline.
ReplyDeleteMarc,
DeleteWell, i guess its possible to lengthen the breech gap to accept full-length streamline foam darts, but the margin of error and seal contact point will be very narrow due to the short bolt movement.
In addition, the chances of jams occurring will be much higher due to the limited length of the breech gap compared to the length of stock streamlines.
An alternative is just to trim the stock streamlines foam darts 1-2cm shorter to allow them to feed and fit into the breech better.
What schedule (wall thickness) is that PVC pipe?
ReplyDeleteJustin,
DeleteThe PVC pipe i use has a wall thickness of around 2mm.
I just finished the mod, and my advise is that you do NOT use a pipe cutter to cut the brass. If you do, it makes the end you cut curve in, and the pipes wont fit in each other. Use a dremel cut-off wheel instead.
ReplyDeleteMarc,
DeleteYes, for brass breech mods, the brass tubes have to be cut with a Dremel. The pipe cutters are only suitable for the PVC pipes or the plastic bolt.
Hey sgnerf, I juz fin the mod but it's not functioning properly. The darts wun fire unless I muzzle feed the darts. I Duno wads wrong with it. Your help is most appreciated. Thanx
ReplyDeleteInuyasha,
Delete"Muzzle feed" as in loading the foam darts via the front of the barrel? Not via the open breech?
If it can only fire in that method, then check that your foam darts are not too wide, as that can sometimes result in them getting stuck in the barrel during the chambering process.
Yes. Loading from the front of the barrel. I m using the sdl dart n I tried shortened nerf darts. Both cnt fire oso. Cn I have the exact measurement of the 17/32 n 1/2 inch brass tube tt is protruding out frm the 9/16 brass? Thanx
ReplyDeleteInuyasha,
DeleteAre both types of those foam darts using narrow tips?
Those foam matched with narrow tips should still be usable in this blaster (though Nerf streamline foam tend to be abit too narrow for 9/16" brass barrels, but should still work).
Re-check your overall system again to find out which part is causing the foam dart to get stuck in the barrel.
Make sure the foam darts are chambered fully into the barrel, not just getting pushed in halfway and the bolt retracting before it gets fired out.
Is there anything you did which differ (even slightly) from the steps in my guide?
The 17/32" and 1/2" brass section in my brass bolt extends out around 1cm from the 9/16" bolt assembly.
The system is designed so that there is the same 1cm amount of nested seal with the 9/16" brass barrel when the breech closes.
Sgnerf,
ReplyDeleteI will give it a try again and c how it goes n will update u if I succeed or failed again. Thanx for the pointers.
Sgnerf,
ReplyDeleteI attempted the mod again, but it resulted the same. Iszit possible for mi to let u take alook at my stampede to c where did I go wrong? Thanx
Inuyasha,
DeleteWell, i guess you could take a video of your stampede internals or take some clear close up photos of the internals and foam darts you use. Just post up the links and i'll see if i can spot any issues from there.
Sgnerf,
ReplyDeleteI would prefer to send it down personally to let you take alook. Would that be possible?
Inuyasha,
DeleteSorry i don't do meet ups just to troubleshoot blasters, no time to do such things. I have received many similar requests from modders but end up they could just check in more detail and solve it themselves.
An alternative is to bring your blaster to the next Nerf game organized at the NerfSG forum, then let the experienced modders attending check it out and help you troubleshoot it.
Sgnerf,
ReplyDeleteOkay,I understand. So where cn I post the close up of my stampede? Thanx for the suggestion.
Inuyasha,
DeleteJust take the photos, upload them to a photo sharing site like Photobucket or Picasa, then post up the links to them.
Sgnerf,
ReplyDeleteHey finally solved the issue with the stampede, it was the teflon tape problem. What type of foam darts r u using? Because nerf stock darts and sdl darts do not fire far. Thanx
Inuyasha,
DeleteGood that you've finally solved the issue.
Honestly, when i asked this question in my earlier reply comment to you:
"Is there anything you did which differ (even slightly) from the steps in my guide?"
And if you had just mentioned using teflon tape in your plunger, then it would have been easier to spot that issue (which many modders have also made the mistake of doing), it would have saved all the hassle. :)
Anyways, as for foam darts, i use custom calibrated ones designed for consistency and accuracy, you can read up on an example of how to make them in my foam dart calibration guide. Just type "calibration" on the search box on the right column of this site to find that guide.
Sgnerf,
ReplyDeletei never thought something so minor can have such adverse effect.Yes i have seen that calibrated guide. But somehow my stampede fire much further when i muzzle feed than when i clip fed the thing. So i do not think that the OD of the dart is the problem. What could be causing it?
Inuyasha,
DeleteMaybe your brass breech seal is somehow not 100% when you use it when clip-fed, check the alignment of the system again.
Did you do anything to the brass barrel? ie, dent it or make it narrower? 'cos that might cause the foam darts to encounter extra resistance during chambering which might explain the difference in performance.
Imho, there could be other things you did on your mod that you didn't indicate which affect it, 'cos the issue seems unique to your unit.
sgnerf,
ReplyDeleteOther than the teflon, i have followed as closely to ur guide as possible. So i m really puzzled what could be wrong with it.
can you suggest any other type of PVC to use?
ReplyDeleteKira,
DeleteWell, the guide cover basically requires any tubing material that can nest smoothly with the 9/16" brass tubes.
Even if the tubing material doesn't nest perfectly with the brass tubes, its still possible to adapt the brass to fit.
An example is the 1/2" SCH40 PVC pipes that modders in the USA use, it is loose for 9/16" brass tube, but they use electrical tape to adapt the brass tubes to fit in those pipes.
Modders in Australia use 20mm orange conduit pipe, and they work too.
Even the SingaPlastics PVC pipes modders in Singapore use also need to be checked to find the ones that can fit the 9/16" brass too... inner diameters can vary amongst the same spec of pipe, due to variations in PVC pipe production.
The best thing to do is just take a sample of 9/16" brass tube and visit your hardware or plumbing shops to test fit in the various PVC pipes available, hopefully you can find one that fits well.
So There is absolutely no chance that you will make one of these breaches and possible sell it? You are obviously the best at this.
ReplyDeleteGmcnerfproj,
DeleteSorry, i don't do contracts or commissions for blasters or parts. :)
I know this is out of context, but since there is now way to "request" posts and this is the most recent post, I figured I would post this here. My request is could you do an internals guide of the Nerf Nite Finder? Thank you!
ReplyDeleteme,
DeleteYou can check out a photo of the Nite Finder internals in this link:
http://i380.photobucket.com/albums/oo244/cheesypiza001/NiteFinderinternals.jpg
Btw... you can also check out internal photos of the rest of the older blasters at the NerfHaven forum:
http://nerfhaven.com/forums/index.php?showtopic=15558
I have noticed a handle or something on the back of your SMG Stampede in a couple of photos and I was wondering what that is. Does it serve any purpose of is it merely cosmetic?
ReplyDeleteThanks
Will,
DeleteGood observation!
The handle is actually designed so that i can hook the Stampede on my belt as a sidearm/secondary blaster ('cos its too large to fit into a holster and i'm not a fan of using rifle slings). It's basically made from a re-purposed window latch. :)
How/What would be the measurements for the use of streamlines?
ReplyDeleteUnknown,
DeleteThe breech gap in my current design is the maximum gap length that i've tested so far to still retain a reliable bolt to barrel seal. The gap could be extended a few mm more but you'll have to be very accurate in the parts fit or it'll affect the seal.
You could actually just shorten stock streamlines by 1-2cm and use them in this breech design, but note that the chances of jams tend to be higher due to the longer length of the foam.
Just plain stinkin' awesome! Thanks for the breech guide. Seriously, you have some of the flat-out best guides. Please keep up the good work. I keep checking back to see if you've been posting and miss the updates for Mod Works, though the SG Nerf has totally rocked. Thanks for responding to everyone's questions so thoroughly and professionally, too. Cheers.
ReplyDeleteX,
DeleteThanks for the nice comments! Appreciate it. :)
Where can I get some of that PVC? Is there a place online?
ReplyDeleteGmcnerfproj,
DeleteSo far, i've not spotted that PVC brand online before... i get them directly from the local plumbing supply shops in Singapore.
I guess you could check at the plumbing/hardware shops around your area. Just bring along a length of 9/16" brass tube to test the fit and find a suitable pipe for it (other brands and types might fit too).
SG Nerf,
ReplyDeleteI was just wondering if I do the barrel breech will it work well with the standard orange streamline darts? I just don't want to ruin my plunger mech to find out that it doesn't work. Also I saw someone ask where to get the brass tube from K&S and I found a great site where I ordered mine for the longshot breech and there prices are cheep so this is the link for that for anyone who wants it: www.hobbylinc.com (also they ship out of GA so its not international shipping)
Romperhouse10,
DeleteWell, my Stampede brass breech design is meant to use short length foam darts (aka stefans), this is due to the inherent limitation in the maximum breech gap length and the need for a secure bolt to barrel seal connection.
Alternatively, you could try trimming your streamlines 1-2cm shorter and test them out, the brass breech system might be able to chamber them too (though the accuracy and consistency of streamlines aren't as good as stefans).
Or you can now use elite darts because of the new design you can cut them down.
DeleteSG Nerf,
ReplyDeleteTrimming them down is an option I suppose but is there any way I could adjust the brass tubing measurements to suit the stock streamlines more efficiently? If so what would I change?
Romperhouse10,
DeleteTo increase the breech gap length, you could shorten the 1/2" and 17/32" brass bolt parts by a few mm, then that could allow the breech to gain slightly more clearance.
But doing so may affect the performance as the duration of the bolt to barrel connection would end up shorter, so the bolt may retract and open before the shot is completely fired, this could result in mis-fires and jams.
Note that using full length foam darts generally tend to result in more jams when the clearance is too narrow at the front and back of the breech gap, 'cos the foam darts may not advance up in time before the next chambering cycle starts and the bolt starts to close. This is especially so when its modded for faster rate-of-fire.
Just some tips to consider. :)
SG Nerf,
ReplyDeleteYes I will mess with it! Thankss!
I may be being ignorant here, but could you please give me some specifications on those darts you used? I really like the way they performed and I would really like to make a few hundred of my own :). Your mods tuts area a huge help, I have referred to them countless times and your reviews have drawn the line between purchasing certain blaster on more than one occasion.
ReplyDeleteThanks
-Dan
Dan,
DeleteThanks for the nice comments! Appreciate it.
The stefans i use are created from custom made silicone tips and foam (cut to 3cm lengths), you can order those silicone tips and foam materials directly from inform3r at the OzNerf forum... or if you are in Singapore, from hanzo at the NerfSG forum. :)
Does this fit streamlines? If not what would I have to do to make it fit them? How far would this shoot with a 13kg spring?
ReplyDeleteSAFEmodding,
DeleteAlthough it could be possible to lengthen the breech gap measurements abit more to fit full length streamlines, there is a risk that the system may not seal properly due to the limited fore and aft movement of the bolt and plunger, and the chances of jams or mis-fires would be higher using such foam darts.
An alternative is to try trimming streamlines 1-2cm shorter and see if they can fit with the existing design.
I've tested it with 13kg load springs and the ranges increased by another 5-10ft, but it also resulted in a slower rate-of-fire and much higher wear and tear in the parts.
Overall, i still find that 9kg load springs are more effective and reliable for Nerf games.
What would i need to do to get it to fire streamline length darts
ReplyDeleteCheers
TOM
MercilessRezno,
DeleteYou could try shortening the brass bolt section slightly to try to accommodate normal length streamline foam darts, but due to the very narrow tolerance of the breech gap, it might affect the proper sealing of the breech to barrel system.
In addition, its not advisable to use full length foam darts in such systems because the chances of jams will be very high, especially if the blaster is also modded to achieve a faster rate-of-fire.
An alternative is to just shorten the streamline foam darts by 1-2cm, which may help improve the firing reliability.
Hey Sg,
ReplyDeleteIt's Dan again. I'm adding up the amount of brass I need for my BB's [I'm planning on doing the longshot and stampede at the same time] and the amount of 9/16 brass that I need is 2 feet and 2 cm. Of course I don't want to buy 3 feet of brass and not use ~28cm of it, so what effect will shortening the amount of brass I cut for the stampede barrel from 21cm down to 19cm have? should I just use a shorter length of brass and leave it at that or should I cut down the barrel as a whole so that no section of non-brass material comes into contact with the dart?
Thanks,
-Dan
Dan,
DeleteShortening the Stampede's brass barrel from 21cm to 19cm will still be within optimal length for 9kg load spring configuration.
I've tested various brass barrel lengths all the way down to 16cm (approx 6") for Stampedes and the ranges achieved were still around the same, so its possible to use slightly shorter barrel lengths. :)
Cool, thanks. You just saved me $8 :)
DeleteHey sg , wanna ask where else can I find the brass tube 9/16 ,I went down to the hobby shop at Chinatown .its out of stock . Regarding the Dremel 767-01 can we find it in sg ? And the diamond cutter is a separate item right ? Need advise thanks
ReplyDeleteDesmond19,
DeleteWell... NTC Hobby at Fook Hai Building is where most of us local modders get the K&S brand brass tubes from too, if they are out-of-stock, then you'll have to wait until they re-stock.
An alternative is to check at ArtFriend shops, they might have stock... but note that their prices are usually double to triple more than at NTC Hobby.
Another alternative is to post a "Want-To-Buy" thread at the NerfSG forum indicating that you are looking for specific brass tubes, some modders there who happen to have spares might be willing to sell some to you.
As for the Dremel 767-01, its been replaced by the newer generation Dremel 7000/N, you can now get it directly from SG Tooling shop at Fook Hai Building #B1-28, here is the product link:
http://shop.sgtooling.com/index.php?act=viewProd&productId=274
Dremel accessories like diamond cutting wheels are sold separately, you can also get them from the SG Tooling shop too.
If i were to do the "smg" conversion mod and cut off the majority of the fake barrel would i see a decrease in accuracy. I would appreciate your insight
ReplyDeletematamata,
DeleteAccuracy depends on the type of foam darts used, if you are still using streamline foam darts they they will be even more inaccurate... but if you are using custom calibrated foam darts or stefans (after you have done a brass breech conversion), then the accuracy will still remain high.
oh ok, i was reading some of the other posts and one poster said that his stampede would not fire correctly when clip fed because of the teflon tape.
ReplyDeleteWhen he refers to this teflon tape is it the procedure in which you apply tape under the o-ring. Is this not recommended. Thank you
matamata,
DeleteYes... some modders put teflon tape under the plunger o-ring in an attempt to create better seal, but it ends up causing too much resistance in the plunger, resulting in the Stampede not working properly.
thank you, so does this mean that as long as i make sure i dont put too much tape under the o-ring then it is ok?
ReplyDeletematamatam
DeleteYou'll have to test to find the right amount, each Stampede is slightly different so its just a matter or testing and adjusting accordingly.
Hello, because i dont live in singapore singaplastics pvc piping is not available to me.
ReplyDeleteso just to make sure, as long as the pvc creates a snug fit in the 9/16 its fine correct? Also if i were to cut down my streamlines would they jam less frequently with the brass breech?
matamata,
DeleteYes, you can use any pipe or tube material to make the guide cover, as long as it fits the brass tubes perfectly (not too tight, not too loose) so that the barrel and bolt are kept in constant alignment during operation.
Its possible to use streamlines in this brass breech design if they are trimmed shorter, the shorter they are the more reliable the chambering process would be... but note that using streamlines in such modded blasters will result in poor range and accuracy (they will curve and swerve erratically in flight), due to the unbalanced nature of streamlines.
Hey, Love your work! I was looking to buy your kit with:
ReplyDelete- Aftermarket 9kg load spring
- Aftermarket o-ring
- Plunger padding
However, I was also looking to brass breach my stampede and live in the US so finding your materials is harder. Is their anyway you could also add the materials for the breach? I don't have a dremel, so if you could cit the materials also that would be very appreciated. Do you have an suggestions as to what type of darts to use with this? Do domes work well and from your expierence what is the best length?
Thanks!
Nerf Modder,
DeleteSorry, i don't have anymore of the materials or brass tubes to spare.
Btw, you don't necessarily need to use the exact same PVC pipe material that i use, just check at your local plumbing stores for suitable alternatives (bring a sample brass tube to the store to test fit the various pipes).
As mentioned in my guide, the breech design is meant for customized stefans. Best performance will be with 3.25-3.5 cm length stefans that have 0.9-1.1 gram tip weight. You'll have to test and find the best combination for your setup.
Thanks for the speedy reply! Do you use an online seller for your brass? Also I have tried to contact inform3r but he has not replied. Do you still get your darts from him? Lastly, I am confused on your instructions for th pvc. You say place the clip and cut. How far away should the clip be from the end?
DeleteNerf Modder,
DeleteI get my K&S brand brass tubes from a local RC hobby shop in Singapore, but they seem to be constantly out of stock... too many modders around i guess. :)
Perhaps you can try checking at online sites like Amazon.com or eBay, might have sellers there. Alternatively, just visit the hardware or hobby shops around your area, see if you can find them there too.
I get my silicone tips and foam through hanzo at the NerfSG forum, who in turn orders in bulk from inform3r at OzNerf forum... maybe inform3r is currently busy, so his response is delayed.
As for the PVC guide cover, just leave a short section at the back end to be glued to the orange guide ring. Match with it and cut accordingly. You can see how much pipe to leave in these photos:
http://3.bp.blogspot.com/-UOSC3qyqdZo/Txt_1O11BWI/AAAAAAAAEik/PZFoOx6ixk4/s400/Stampede%2BBrass%2BBreech%2BMod%2B-%2B11.JPG
http://4.bp.blogspot.com/-xu0cd1J-mWA/TxuAGxXLaBI/AAAAAAAAEjg/SrjxinAtFhw/s400/Stampede%2BBrass%2BBreech%2BMod%2B-%2B19.JPG
The rest of the PVC guide cover is just to encase the brass barrel.
thanks for the advice sg, anyways, regarding the pvc guide cover, i was looking around in my local hobby shop and i thought that 5/8 brass would be fine to fit over the 9/16. However, before i continue i would like to know if you believe this is just right or too loose. This is because i am rather unsure to whether or not the 5/8 is too loose for the 9/16 brass.
ReplyDeletematamata,
DeleteI'm not familiar with 5/8" brass tubes (never used them before)... i think its best if you just bring a length of 9/16" brass tube to the hobby shop to test and see if it can nest within the 5/8" one.
SG Nerf,
DeleteI'm wanting to build this for my Stampede however I am concerned about the amount of time that the bolt will have to connect to the barrel, because my Stampede runs off of two 9.6v batteries wired in series for faster rate of fire. Do you have any idea how this may affect the performance of this breech? Also I was wondering how tight of a fit streamlines have in the breech and if it's worth modifying the breech or trimming down streamlines vs. taking the time to make my own darts.
Austen Cline,
DeleteWell, so far i've tested until 16.8V with 4 x fully charged unprotected TrustFire Li-Ion rechargeable batteries and that setup works nicely.
I guess you'll just have to test your particular voltage setup and see if it works. If its too fast, then just reduce the voltage feed accordingly.
As for my brass breech design, its meant for short-length stefans. Longer length foam darts could be used but they'll tend to decrease chambering reliability and result in jams.
Trimming down streamlines could work, basically the shorter they are trimmed the more reliable the chambering process (the bolt has more time and space to retract while the foam dart advances up in position).
But note that streamlines are inherently unbalanced so even if the blaster can fire them, they will still swerve and curve all over the place so they're not a reliable option for actual games.
Making customized stefans with the right length and tip weight will be the best in terms of consistency and accuracy.
Okay thanks. I realize all of the things about dart length and the inconsistency of Streamlines I'm just wondering how snugly they feed into the barrel.
DeleteAusten Cline,
DeleteFor streamline foam darts, they generally tend to have a loose fit in 9/16" brass barrels... but i've noticed that streamline foam can also vary quite abit between production batches, some are narrower than others.
Just test them by slotting the streamline foam dart into the barrel and tipping it downwards. If the foam dart drops out then its too narrow, which indicates that its performance will be affected due to the air escaping around the foam during firing.
The best foam will be those that can sit snugly in the barrel, creating a good dart to barrel seal (not too tight nor too loose).
Hi SG!
ReplyDeleteWhat is wrapped around the 13mm pvc pipe right at the receiver? Is it a coupler or a piece of 16mm pvc? I'm about to attempt this mod, and I'd love to know what that is and why it's there.
T da B,
DeleteIts a ring of 16mm PVC pipe, that just acts as a spacer to help keep the 13mm PVC guide cover aligned with the casing internals.
You can also just use layers of duct tape or any suitable spacer material.
Another thing, SG--you didn't follow the line you drew exactly when dremeling the guide cover, did you? I ended up putting a lot of scratches into the guide cover when dremeling the smaller parts of the clip outline. Any tips on how to get it as clean as yours?
DeleteT da B,
DeleteWell, what i do is just cut the basic straight lines with the cutting disc, then simply use a sanding bit to sand and shape the rounded corners. That's the usual method most modders use too. :)
hey, sgnerf, Ive been interested in this mod, but without the dart door, how can it possibly load?
ReplyDeleteAnonymous,
DeleteAs mentioned in my guide, the stock stampede plastic breech does not have an air-tight bolt to barrel seal, hence the plastic bolt itself is essentially the barrel.
In order for the stock breech system to work, it needs to have a dart paddle blocker door to block the foam dart to allow the stock bolt to sleeve over it during the loading process.
But in a brass breech system, the brass bolt itself pushes the stefan into the brass barrel, and when both the brass bolt and barrel connect together they form a 100% air seal for optimal firing power and range. The stefan fits within the brass barrel perfectly and is kept in position before it is fired out.
That is why the brass breech does not use a dart paddle blocker door in its design.
Ok, thanks, and one other thing, for some reason, the bolt keeps hitting the thing in the clip that pushes the darts up, resulting in a jam every time, is there a good way i can prevent this? I made my bolt about 9 cm, (oops), could that be the problem?
ReplyDeleteAnonymous,
DeleteThe bolt should naturally slide over and push down the dart advancement platform in the clips after the last stefan is fired (that part has a ramped shape anyways), so it shouldn't be the cause of jams... or are you referring to another part?
Maybe you just have to check the alignment of the parts, could be something else not positioned correctly and causing the jams.
alright, I think I fixed it,i sanded the clip platform so its a little less steep and it fires fine now
ReplyDeletehey, one last thing, are stefans thicker then normal streamlines? because Im using shortened streamlines in mine and all 18 of them are very lose in the barrel (if u put one in and tip it the darts fall out easily) are stefans this way too? or can i just make the barrel 17/32?
ReplyDeleteAnonymous,
DeleteIt depends on the foam or foam back rod (FBR) material used to make the stefans, but generally most modders usually use stefans with wider foam diameter.
Such stefans have a snug fit in 9/16" brass barrels or 0.528" ID PETG barrels, which are the 2 most common barrel dimensions used by modders.
They sit nicely in those barrels and will not drop out if the barrel is pointed downwards.
Streamlines are usually narrower so they tend to have a loose fit in those barrel materials.
One of the ways to adapt the barrels to use narrower foam darts is to make a few tightening rings on the entrance section of barrels (check my Longshot brass breech guide to see how its done), this will help hold the foam darts in place before firing and yet still allows the use of the wider diameter form darts.
You could also use 17/32" brass barrels too, but note that it would limit your options when using stefans, because you will not be able to use the wider diameter variants (which are more commonly used amongst experienced modders).
OK, thanks
ReplyDeletehey, I'm wondering what kind of fbr you use, because mine does not fit in the 9/16 barrel and pretty much just falls out when i fire..... is the barrel too big? or should i just get a stronger spring? the air seems to just go around the stefan.
ReplyDeletesam268,
DeleteI currently use either the custom red foam (sourced from inform3r at OzNerf forum) or the beige FBR (sourced from Zinv/Backspacer at the NerfSG forum).
The custom red foam has a snug fit in 9/16" brass barrels and 0.528" ID PETG (both common barrel types amongst most modders), the beige FBR is also snug fit after being heat treated properly (i basically heat the FBR slightly in a cloth bag with a hair dryer until they are the right dimensions).
Getting the right foam and FBR size is important... they can very alot in diameters (even if the specifications state 1/2" diameter, and even amongst the same batch of foam or FBR), so you have to test and see which are the best fit for your barrel type.
If its too tight, then the ranges may drop due to too much resistance (or it just gets stuck)... if its too loose then the air leaks around the foam and results in low ranges too (as you've experienced).
The test is to slot the foam or FBR in the barrel (it should not be too tight that it is difficult to slot in and gets stuck)... then tip the barrel downwards, the foam or FBR should not drop out. It has to be a perfect snug fit, not too tight, nor too loose.
Ok, thanks! I'm using AcE Hardware fbr, which is a PERFECT fit in the 17/32 in. tube, so im using that as my barrel and I'm getting 80-90ft ranges with a 8kg spring, and 4 4.2v trustfire batteries as you recomended.
ReplyDeleteMay I ask where you got your dremel and accessories from?
ReplyDeleteExcellent mod also, I plan on trying to replicate this eventually, or would you recommend doing something similar to a different gun like something from the new nstrike line for even greater range?
A5phyx1a1on,
DeleteI ordered my Dremel online from Amazon.com, but you can also get them from the larger hardware stores too.
The brass breech mod is best done on blasters with larger plunger volumes (to get optimal performance)... so an alternative blaster to do this mod is the Longshot, it still has the largest plunger volume amongst all the Nerf blasters to date and can achieve even longer ranges after modding (though its a manually primed bolt action blaster, so its rate-of-fire is slower):
http://modworks.blogspot.com/2010/03/nerf-longshot-brass-breech-mod-guide.html
Hi I want to start off by saying I love your mods, and i wanted to know what type of silicone tips you use on your on your darts and where do you get them? Keep up the awesome work. :D
ReplyDeleteAvenger747,
DeleteThanks for the feedback! :)
The custom silicone tips i use in my stefans are sourced from inform3r at the OzNerf forum, you can order them directly from him.
If you are in Singapore, you can order similar silicone tips from hanzo at the NerfSG forum too.
Hi, I know this is a dumb question but where can i buy a nerf stempede in Singapore? Cant seem to find it. Haha Thanks :D
ReplyDeleteStampede ECS*
DeleteAnonymous,
DeleteNerf Stampedes are currently sold out locally... i guess you'll have to wait for them to be re-stocked, or order them in from overseas or online stores. :)
Thanks :D
DeleteHi SG,
ReplyDeleteHow did you keep the PVC sheath from spinning or getting pulled out of the blaster?
T da B,
DeleteAs mentioned in the guide, i glued the PVC guide cover to the orange collar piece behind:
"The orange collar piece is also positioned and glued to the PVC guide cover to establish a fixed securing point to the blaster casing."
Here is the photo of it:
http://3.bp.blogspot.com/-UOSC3qyqdZo/Txt_1O11BWI/AAAAAAAAEik/PZFoOx6ixk4/s400/Stampede%2BBrass%2BBreech%2BMod%2B-%2B11.JPG
Ah I can't believe I missed that! Your solution is so simple and elegant--I was going to epoxy sheet metal to my PVC sheath, but your solution is much better (and modular!). With this info, I can now put the finishing touches on my Stampede. Thanks again, SG!
Delete~T
SG,
DeleteTragedy has struck! My breech does not move far forward enough to create the seal before "firing". I made sure that when my breech is all the way forward, it slides completely into the barrel, like in one of your photos. Did you have to mod your trigger catch activator to release later? Is there a specific way to align the plunger teeth with the main driving gear? I know my measurements were accurate!
T da B,
DeleteMost likely the position of the brass barrel within your PVC guide cover needs to be moved further back abit so that the brass bolt can reach it to create the seal.
I guess when you tested the bolt movement on its own with the casing open (by manually pushing it back and forth), it may look like it can connect, but the actual movement of the bolt during operation could be slightly shorter.
The difference could be just 1-2mm, so you need to adjust and tweak the bolt and barrel positions.
Made some slight adjustments and it shoots like a champ! The only problem now is that my gears have stripped lol. Fortunately, I had the pleasure of enjoying a few shots that went straight through a Nerf box before the gears died :) Thanks again for your help, SG!
DeleteHi, I have the doubt if the foam from streamlines creates a great seal with the 9/16 brass (i dont use stefans) or would it be better to use the 17/32 brass in this design? I plan to use the foam from streamlines to create darts similar as yours, but i am uncertain if it fits tight or not.
ReplyDeleteAnonymous,
DeleteStreamline foam tends to be too narrow and therefore a loose fit in 9/16" brass tubes.
As for 17/32" brass tubes, it depends on the batch of the streamline foam, 'cos there seems to be some variation between batches, some can fit but some cannot, so you have to physically test the fit to find out.
Note that if you use 17/32" brass tubes as barrels, you'll be limited to only being able to use narrow foam darts.
Most modders use 9/16" brass tube for barrels 'cos they can add tightening rings to adapt to narrower foam darts if required, yet still be able to use wider customized foam too, this allows for more flexibility in foam dart usage.
Just wanted to add some tips for people who may be experiencing uncontrollable firing of the bb-pede when its activated. Try loosening the plastic collar, as when that is fully tightened it 'pinches' on the PVC guide, slowing the return rate of the plunger which leads to that uncontrolled "gundam" firing.
ReplyDeleteCheers
:)
Hey, SG, like I said a while ago, not sure if this blog is still active, but I kinda need some help here. My stampede was finished a while ago, and it turned out great, I did every mod possible.... But... I changed your design a little..... Your design did not work when I attempted to do it (Not you, I am just an idiot) and so instead of having the bolt push the dart into the barrel, I made it so that the dart loads in the bolt, but the bolt is now made of brass, thus a tighter air seal. I got about 40 feet more after doing this, and I like using the elite darts or stefans in it. HOWEVER, I am now noticing small "nibbles" in the back of my darts after firing. 3 or 4 is not enough to change performance I don't think, but some have been shot many times, and the whole back of the dart has been "nibbled" away. I think the sharp brass edge is clipping the back of the darts when loading, and I think it's cliping the dart "on deck" if you know what I mean. Because when the darts get seperated from the clip, the bottom of the bolt clips the top of the next dart in the clip. Any ideas?
ReplyDeletesam268,
DeleteI'm guessing your design makes the foam dart get pushed backwards into the narrower brass bolt and that probably increases the chances of the back part of the foam dart getting clipped between the brass tubing each time and bitten off (due to the difference in tube size between the barrel and bolt).
I guess you could to try sanding the entrance of the bolt side so that its less sharp and more rounded, it might help.
That is one of the things that my design helps to avoid as it pushes the foam dart into the barrel instead, so the chances of it clipping the foam are minimized.
ok, I have sanded it and bent it into a little better shape. It is getting similar ranges and the bites are far smaller, if at all. Thx!
DeleteI have performed the mod but the darts tend to jam a lot causing double firing. Do I need to sand down the entrance to the bolt and bend the bolt so that it is properly aligned or is there anything else you can suggest? I am using 3cm stefan darts. When it does work I am getting 120ft flat with an 11kg spring.
ReplyDeleteFUBAR,
DeleteSanding the bolt to create a smoother beveled edge and improving the alignment can help, but since your modded Stampede can already fire well, it means the system is air-tight and working properly.
The jams and double firing are probably due to some extra resistance in the overall setup (ie. there might be uneven surfaces in the pipes or tubes causing friction, or the alignment is just slightly off), so the bolt return stroke is abit slower and ends up moving back only halfway before the firing cycle repeats again, hence half-feeding the next stefan and causing jams or double firing.
What you can try is to apply grease in between the moving brass and PVC tubes which are in contact with each other, that can help to reduce friction enough to solve those issues.
Thanks SG Nerf.
DeleteI will give that a shot.
Hi SGNerf,
ReplyDeleteLove the mod and have performed it myself with Singaplastics PVC however I do have a question. Are K&S brass tube measurements quoted in OD are inner Diameter? Curious as to how a 9/16 inch brass tube (or 14.2mm) fits inside a 13mm singaplastics pvc. I only ask not because I am questioning this but only because I am trying to find a suitable substitute for the singaplastics PVC as I have run out and need to know what the inner diameter of the tube I need is.
Anonymous,
DeleteThe K&S brass tube label measurements are based on outer diameter (OD).
Note that the 13mm SingaPlastics PVC pipes are not exactly 13mm inner diameter (ID), they are not made to precision measurements. There are also 2 production versions, thick-wall and thin-wall (which has a slightly wider inner diameter).
The inner diameters of the PVC pipes can even vary a further 1-2mm within the same length of pipe too... therefore not all SingaPlastics PVC pipes labelled as 13mm can fit, i have to physically test each individual pipe to find ones that can fit the 9/16" brass tubes, so that it can be used for the mods. :)
Thanks SG Nerf, that must be a real PITA to test each one. Ever thought of using 14mm ID carbon fibre? I might give it a try and let you know how I go.
DeleteAlthough the cost may be significantly higher it is more readily available in Australia. You can get 14mm ID in Aust for around $20 for 1 mitre.
FUBAR,
DeleteYeah, any suitable sized pipe or tube can be used... i've heard of some modders using stuff like electrical conduit pipes and even plastic tubes from broom handles, i guess anything that can fit will work too. :)
SG if I put a piece of Brass in my stock stampede breech will it perform as smoth as stock and if it does how much extra range I will get.
ReplyDeleteAnonymous,
DeleteWell, i guess putting a piece of brass into the stock breech could help create a tighter seal in the stock bolt... if its done right, you'll probably get some range improvement (maybe 5-10ft more, depending on the rest of the mods done), but the problem with that method is that it could end up causing issues with the foam darts chambering properly into the narrowed bolt, so it might create more jams. You'll have to test and see if it can work reliably.
Hi can you please do a fps test on this blaster? With a chrony, I was wondering what sort of velocity you would be getting.
ReplyDeleteAnonymous,
DeleteDepends on the type and weight of stefans used, but based on 1.0 gram tip weight stefans, last i tested, the FPS averaged between 170-180.
sg nerf can you pls tell me where yo get the singaplastics 13mm pvc pipe?
ReplyDeletebalraj singh,
DeleteI got my SingaPlastics pipes from shops along Jln Besar, you can try a shop called Wah Leong Co, which stocks a wide range of those pipes... there are many other shops there which sell the same pipes too so you can just have a look around to find them.
hi sg nerf can u pls tell me where u buy your dreml
ReplyDeletein sg or online
tks balraj
balraj singh,
DeleteI ordered my Dremel 767-01 in from Amazon (its a battery operated model so no issues with voltage), but that was many years ago so its probably not available or superseded already.
You could also check at local hardware stores like HomeFix, they also stock the various Dremel models too.