Some users who have modded their Nerf Stampedes may have encountered an odd issue whereby their blasters continue firing even after they release the trigger, resulting in erratic firing operation... or the bolt moving to and fro but the catch not releasing at all.
Here is a possible cause of this phenomenon:
The Stampede's Plunger Catch Control Spring has somehow popped out of position and no longer functions properly.
The solution is to remove the catch control component and reposition the spring back to its original position, then install it back into the Stampede.
Applying some tape to cover the gaps can also help prevent the spring from popping out again too.
This should help solve the Stampede's "auto-running" or erratic firing issues... or at least narrow down the causes. :)
what is catch control component?
ReplyDeleteethan1000,
ReplyDeleteIts the component shown in the 2nd photo.
That item pushes the plunger catch upwards to release the plunger rod which compresses the air in the plunger and fires a shot.
Hi SG Nerf,
ReplyDeleteIn your opinion, is this linked to the issue some people are experiencing with increasing voltage on their Stampedes? Is the faster ROF causing the spring to pop out of alignment? Or, is this a similar but unrelated issue?
Thanks!
tigerxchaos,
ReplyDeleteYes, so far from my experience working on dozens of modded Stampedes and along with the experience of other Stampede modders, we have found that mis-aligned or bent plunger catch control springs are one of the main causes of erratic firing operation.
Higher RoF can increase the chance of the spring popping out, but i have seen it occur in stock Stampedes too.
Therefore if any Stampede user notices something odd with their unit's firing operation, one of the first things to check is the plunger catch control spring.
SG nerf sometimes the spring will still come out after u put it back.i solve this by glueing a small plastic were the spring comes out maybe u could try this? btw i got the plastic from the removed AR
ReplyDeletelmix,
ReplyDeleteYup, as mentioned in the guide, i attach tape to cover the gaps to prevent the spring from popping out again.
Just to update, i'm now using stronger aftermarket plunger catch control springs which help to further improve the firing operation and reliability, especially at higher RoFs.
If you are keen on one, i currently have a sales thread with Stampede Mod Upgrade Kits available at the NerfSG forum (www.nerfsg.com) trading section. :)
Hey SGNerf,
ReplyDeleteI seem to be having this same problem, except, the spring isn't jumping out of position, for some reason it just keeps auto-firing- any idea what the cause may be? I've up'd the voltage to 15-16 volts and have a 9kg load aftermarket spring.
Hey again,
ReplyDeleteCorrection, the plunger catch spring is indeed bent- would you be able to forward the size measurements for me? Aus is incredibly hard to source springs ><
Chi-Rong,
ReplyDeleteIf its not the plunger catch control spring that's causing the "auto-running" issue, then the other main cause is because your plunger return speed is not fast enough.
Check the following parts:
1) Black return plunger spring too weak. Replace with stronger version or temporarily stretch it abit to increase spring load.
2) Plunger o-ring too wide or not enough o-ring lube, resulting in too much friction causing slowdown in plunger return. Replace o-ring or re-lube the plunger.
3) Plunger to casing contact is too tight (due to manufacturing variation in parts fit), resulting in added resistance. Apply lube to the contact areas or trim the areas to loosen the fit.
You can read more about the various causes and solutions to this issue at the NerfSG forum "Nerf Stampede - Troubleshooting Guide" thread, start from this following post link and read onwards:
http://nerfsg.freeforums.org/nerf-stampede-troubleshooting-guide-t1877-10.html#p23131
Hope that helps! :)
Chi-Rong
ReplyDeleteFor the aftermarket plunger catch control spring, the ones i custom order are 3.8mm in outer diameter and around 32mm in length.
Hey SG Nerf. A Parts List with suggested upgrades might not be a bad idea for those of us who want to make the most out of our mods. A knowledge base, for instance, of what the default measurements of components are and their suggested upgrades would prove very helpful and stop you having to answer the same question twenty times. Even the international crowd in Oz where parts are scarce can order from McMaster-Carr provided they know what they're looking for.
ReplyDeleteJesse,
ReplyDeleteSounds like a good idea... why don't you do it? Then everyone can reference all the individual parts measurements from you too. :)
In order to take out the catch control spring, do you have to unscrew the plunger as well?
ReplyDeleteTim,
ReplyDeleteYes, you'll have to remove the plunger and catch assembly to get better access to it.
Is there anything wrong with gluing the spring so it won't bend out of place?
ReplyDeletekevin,
ReplyDeleteYes, you can also glue both ends of the spring within the plastic parts to secure it, just make sure it does not interfere with the proper compression of the spring.
I modified my Nerf Stampede (changed the spring, changed voltage and increased the size of the hole) and now notice that it crushes and tears the foam bullets. Does anyone know what causes that and what do I need to do to correct it.
ReplyDeleteThanks,
Mikes
mikes88888,
ReplyDeletePerhaps you could re-check the alignment of the bolt and clip? Maybe something is clipping the foam darts or blocking them from being chambered properly.
Though in my experience, its quite common that foam darts tend to wear out faster when used in modded blasters, due to the additional stress of the higher air pressure and faster velocities that are generated.
When I fire my StamPede, it fires and stops, not firing the dart, just leaving it on the plus shaped thing at the back, causing it to jam. When I pull back the jam door, the visible spring returns to it's normal position. Can you help??
ReplyDeletejackholden98,
ReplyDeleteCheck that your batteries are at full capacity (not drained low) as it seems the motor is not receiving enough power to fire continuously.
If you replace the batteries with fresh ones and it still can't work (and you didn't open it up to modify before), then its most probably a mechanism or circuit fault from the factory. I would advise you to just exchange it at the store for a new working unit... no point wasting time trying to troubleshoot that kind of issue.
I just removed my AR, and got it back together. I just test fired it on it's side, and it was already cycling slightly faster. I put the rest of the screws back in, shouldered it, and it misfired about every 3rd shot, audibly firing slower and making a louder BANG. It still works perfectly on either side, just not vertical, like it's supposed to be functioning. Could that possibly be this spring, or something else entirely?
ReplyDeleteCorrection: the loud bang is when it fires properly...it won't fire at all on its sides, and jams about 3 darts.
ReplyDeleteUnknown,
ReplyDeleteYou probably have components mis-aligned, open it up and check that all the components are positioned properly (especially the moving parts and small springs).
Update: I got it back opened up finally, and the plunger catch spring was sticking out from under the bracket. Basically, when it was vertical, occasionally the catch would actually hold the plunger due to gravity. When it cycled fast, it was moving the plunger with the whole bolt assembly. So superglue to the rescue!
ReplyDeleteOkay, I don't understand what my problem is. I connected 8 x 1.2v NiMH batteries, and the gun fired at stock speeds. I connected 12 NiMH batteries and the gun fired too fast. I figured something in the middle is what I wanted, but when I connect 10 batteries, the gun will only fire if held in a vertical position (and fire straight up). In summary, it will fire with the stock 6 D cells, 8 NiMH batteries, 12 NiMH batteries, but not 10NiMH batteries. Can anyone tell me why? By the way, the batteries are 2300mah Energizer rechargeable batteries.
ReplyDeleteBad_Bud,
DeleteSeems like the battery holder you used for the 10 x batteries somehow has one or more loose battery compartments which resulted in an erratic circuit connection.
You'll have to check the battery holder with a voltage multimeter to find the loose connection.
I did check it with a multimeter by touching the negative and positive ends on the Stampede battery compartment itself after I had hooked it all up - I did this with every configuration. I hooked the batteries together using electrical tape and wire. The only difference between the 12 x setup and the 10 x setup is that I removed two batteries from the circuit.
ReplyDeleteI originally thought I had really screwed something up in the wiring job, so I ended up rewiring the 10 x configuration at least four times, and every time it gave me proper readings on my multimeter.
What puzzles me is that it will still shoot in a vertical position (reliably) with the 10 x configuration. I checked the springs inside and nothing is misaligned.
Perhaps if you have any NiMH rechargeable batteries, you can hook them up at 8x, 10x, and 12x and see what your results are.
Bad_Bud,
DeleteThats really odd... i've just tested rechargeable NiMh batteries using 8x, 10x and 12x combinations (i used Eneloop batteries) in a stock Stampede and they all worked without issues.
I guess it's something to do with your particular 10x battery combo setup that is causing the connection issue... usually if a setup only works when you tilt the blaster a certain way, it means one of the various points in the circuit is somehow loose.
Try checking that the connection between the battery sled and the blaster itself is secure... just connect up everything, slot in the battery sled, then test the circuit on the internals of the blaster to see if the current is getting through (hold the blaster in various positions to make sure the connection is not interrupted by shifting contacts).
Thanks for testing your batteries in a similar setup. I'll have to give it another go sometime with some better circuitry.
ReplyDeleteSgnerf, my gun is working but no darts are coming out they just stay at the chamer place. How?
ReplyDeleteS'pore Nerfer,
DeleteMost likely during modding you installed the plunger catch plate facing the wrong direction, so the plunger is moving but the plunger rod is not catching, hence its not being primed at all.
The solid side of the plunger catch plate should be facing the plunger (not the other way around).
sg,could i commission you for a minimized stampede? i'd send the stampede.
ReplyDeleteIron Archer,
DeleteSorry, i don't do contracts or commissions.
Maybe you can check with some of the modders at the NerfSG forum, they might be able to do it.
so ive worked with nerf guns for a while and never before come across thiss issue,i have a modded nerf stampede with the AR removed and a voltage increase. i do not know the exact volt. but i am using three 9v batteries hooked in series. i dont have much experiene with stampedes and so here is my issue. the gun when loaded or unloaded will begin to fire but before the plunger will engage all the way it simply dies and will not een dry fire. its not a battery issue because i bought brand new ones and nothing is out of place or broken as far as i can tell. any suggestions?
ReplyDeleteBEARDANSIE,
DeleteOkay, you have to be aware that 9V alkaline batteries have very low mAh, hence their amp current discharge rate (a different factor from voltage) is very low, as such batteries are mainly designed for low drain devices.
Just for comparison, a 9V alkaline battery usually only has around 300-400mAh, while a AA-sized alkaline battery typically has around 2,500-2,800mAh. A D-sized alkaline battery has up to 20,000mAh or more. :)
Amp current discharge is a function of C-rate (which depends on the battery specs) x Ah... so with equivalent C-rate, a battery with low mAh capacity will result in lower amp current discharge rate.
In a Stampede, the motor requires batteries with higher discharge rate to function, as it needs to draw more amp current when under load as it primes the plunger spring. The 9V alkaline batteries you used cannot supply enough amp current to the motor, so it just stalls (it does not matter how much voltage you put in, it will still stall).
You need to use batteries with more mAh (ie. AA-sized batteries and above, for stock spring loads) or batteries with higher discharge rate characteristics (ie. unprotected Li-Ion rechargeable batteries, especially when using even stronger aftermarket springs), then the motor will get enough amp current to pull the spring load properly.
For additional reference, you can check my Stampede Mod Guide for more info:
http://modworks.blogspot.com/2010/09/nerf-stampede-mod-guide.html
thanks for that explanation it helped and i got it fixed, but of course another problem has arose. the gun is firing but the plunger is not catching, the catch spring and plate are in the right place and oriention yet it will not hold the plunger. is it that i need a new spring or is it something else?
ReplyDeleteBEARDANSIE,
DeleteDouble-check that the catch plate and catch spring are all in the correct positions/facing and functioning properly, also check that the plunger rod catch notch is facing upwards too.
You can also try using a stronger catch spring too, but not too strong or else the catch control timing stalk might not be able to push it up to release properly.
If the plunger rod still cannot catch, then another cause could be due to a gear within the gearbox being worn out or broken, or the connections between the gears are loose. You'll have to open up the gearbox to check and troubleshoot it.