Nerf Stampede "Brass Breech" Mod Guide!

This mod guide will look into my "Brass Breech" modification for the Nerf Stampede.

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 when the brass breech 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. :)

Nerf Rayven - Mod Guide!

This Mod Guide will cover some performance mods for the Nerf Rayven.

Mods covered:
- Voltage Increase
- Stefan Compatibility
- Access Hatch Removal

Disclaimer: Modify at your own risk. Modifications may wear out or damage your blaster. Please be careful when using hobby tools!


:: Voltage Increase ::

As the Rayven is a flywheel based blaster, the faster the flywheel motors spin the faster foam darts get fired out, hence longer range and faster dart velocity.

To increase the speed of the motors, simply increase the voltage feed.

In my examples, i use 14500 size 3.7V Li-Ion Rechargeable Batteries (Brand: TrustFire / Unprotected versions) in my modded Barricades. The batteries can be sourced from specialist electronics stores or online sites.

14500 size 3.7V Li-Ion TrustFire rechargeable batteries are usually charged up to 4.2V, so i use various configurations (along with dummy AA batteries to fill in the empty slots if required).

The Rayven has 4 x battery slots (one slot more than in a Barricade), this allows for additional voltage increase options without the need to mod the battery compartment.



In the photo above (from left to right), the voltage configurations are at 8.4V, 12.6V and 16.8V.

I have noticed that the Rayven's stock motors can run on 16.8V without the inbuilt safety thermistor cutting off the power, therefore it seems to have a much higher voltage and current tolerance than compared to the Barricade.

See the test fire video below for the range results based on these various increased voltages.

Note that normal Alkaline batteries have limited discharge rates, and may therefore perform differently at the same voltage compared to these unprotected TrustFire Li-Ion batteries.


:: Stefan Compatibility & Access Hatch Removal ::

As most experienced nerfers will know, stock streamline foam darts are too unbalanced and inconsistent to be usable in Nerf games, especially with modded blasters. They naturally tend to swerve unpredictably in flight. There isn't much point shooting far when the shots can't actually hit anything reliably.

Most modders prefer to use "stefans" instead (short length customized and calibrated foam darts), as they provide more consistent performance and much higher accuracy. For clip-fed blasters, stefan compatible clips would be required.

For reference, you can find an example of a stefan compatible clip using the "guide rod" design Here.

We shall now look into modding the Rayven to be able to fire stefans. At the same time, removing the access hatch to allow for a clearer view of the firing process and for quicker jam clearing.


Step 1: Disassemble your Rayven. Make sure to remove all the screws before detaching the casing and internal components.




Step 2: Remove the dart pusher stalk and drill a hole through the middle of it. Prepare a suitable length of bolt to become a "stalk extender".

In my example, i used a 4cm length threaded steel bolt.




Step 3: Install the bolt into the dart pusher stalk. Use a bolt nut to secure it properly.



If required, this "stalk extender" mod is easily reversible, simply uninstall the bolt to revert it back to stock condition and you can use normal length foam darts again. :)


Step 4: Remove the access hatch piece. Use a strip of tape to wrap around the pressure switch so that it is kept activated. This mod is also reversible too.




Step 5: Install all the parts back into the casing. It should look like this.




Step 6: Adjust the reach of the new "stalk extender" so that it can push the stefans forward properly.




Step 7: For those who create their stefan clips using the "guide rod" design, you will need to extend the guide rod higher until it reaches just below the top-most stefan, this is the prevent the moving dart pusher stalk from dragging subsequent advancing stefans too far back during usage and causing jams.

In my example, i used a short length of wooden rod wedged into my stefan clip's existing guide rod. This is also easily uninstalled, so that it can still be usable for other clip-fed blasters too.




Step 8: Its completed!



Now you have a semi-auto + clip-fed + stefan-compatible blaster!

:: Modified Nerf Rayven - Demo & Range Test Video ::




Notice that the streamlines have a much wider left/right shot spread radius, so they tend to be rather inaccurate at longer ranges.

Calibrated stefans have a much narrower left/right shot spread radius, so their overall accuracy is much better and more consistent.

Also note that there is a fair amount of range variation when the blaster is fired quickly, this is likely due to the flywheels slowing down momentarily between each shot, therefore the key to firing such blasters is to regulate the rate-of-fire for more consistent ranges.

In addition, at higher voltages like 16.8V, the flywheels spin so fast that there tends to be an increased rate of slippage and mis-fires, which results in rather unpredictable shots.

So far in my tests, i've found the most ideal voltage to be at 12.6V for a more reliable combination of improved range and shot consistency.


:: Sample Test Fire Data ::

Ranges are PTG: Parallel-To-Ground (Shoulder height, no elevation).
Distance is measured at where the shot lands (Average of 18 shots).

Stock Rayven (6.0 Volts)
Range = 25-30 ft

Modded Rayven (8.4 Volts)
Range = 35-45 ft

Modded Rayven (12.6 Volts)
Range = 60-70ft

Modded Rayven (16.8 Volts)
Range = 80-100ft

Note that the tests were done under controlled conditions with either stock streamlines or calibrated stefans. The results are sample estimates for reference (your results may differ depending on materials and mod techniques used).


:: Summary & Game Usage ::

Having tested out modded Rayvens in a few Nerf games, i've found it to be quite a versatile blaster for fast-paced gameplay. Its compact form factor is easy to handle and very maneuverable.

The clip-fed system makes a big difference in being able to sustain continuous firepower over extended game rounds (just be sure to equip more spare clips), and the capability to use stefans greatly increases the shot accuracy and hit rate over longer firing distances.

In addition, you can instantly double the fun by dual-wielding 2 x modded Rayvens too! :)
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Nerf Rayven - Internals Guide!

This guide will serve as a reference for the internals of the Nerf Rayven CS-18.

For a detailed review of the Nerf Rayven, click Here.

Nerf Rayven - Disassembled




Nerf Rayven - Internals Layout




Nerf Rayven - Internals Layout (Front)




Nerf Rayven - Internals Layout (Back)




Nerf Rayven - Flywheel System Detail




Nerf Rayven - Motor Comparison with Tamiya Plasma Dash Motor


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Stefan Compatible 18-Dart Clip - Mod Guide!

Most modders who custom make their own foam darts for better accuracy and range use shorter length foam darts which are commonly referred to as "stefans".

The stock N-Strike clip design isn't compatible with shorter length foam darts, as they tend to shift back and forth within the excess space during usage which causes jams (especially in longer clips), so modifications have to be done on the clips to fit them properly.

I've been using stefan compatible clips of various designs for quite a while, but the simplest and most effective design that i've tried out so far is the "guide rod" design.

The "guide rod" design is based on the clip modding technique by JustSomeBob at the NerfRevolution forum and WicketTheModder at the NerfHaven forum.

It is basically a rod that runs the length of the clip and nests within a collar in a hole drilled in the clip's spring loaded dart pusher, this rod keeps the stefans in position throughout. The dart pusher is constantly guided by the rod as it advances the stefans up into the bolt.

In addition, i also make a "slot window" on my modded clips, so that i can view the ammo count too.

Lets start...

Step 1:

The materials i used for this clip mod are as follows.

- 18-dart clip
- 5mm OD K&S brass tube (for the guide rod)
- 6mm OD K&S brass tube (for the guide collar)
- Dremel 767-01
- Selleys super strong 2-part epoxy glue



You can substitute the materials and tools with other similar items, just adapt them to your requirements.


Step 2:

Open up the 18-dart clip casing. As the 18-dart clip casing is usually glued together, use a Dremel to cut along the side of the clip casing. Make sure the cuts are straight and even.



Remember to remove the 2 black machine screws at the bottom of the clip and detach the rubber feet too.


Step 3:

Measure the position of the guide rod based on the length of your stefans.




Step 4:

Mark the measured point on the clip's dart pusher, then drill a hole in it to fit the guide collar.




Step 5:

For the guide rod, cut a 26cm length of 5mm OD brass tube.

For the guide collar, cut a 3cm length of 6mm OD brass tube.



The 5mm OD guide rod will nest inside the 6mm OD guide collar.


Step 6:

Glue the 3cm length of 6mm OD guide collar into the drilled hole in the dart pusher.




Step 7:

Glue the 26cm length of 5mm OD guide rod onto the bottom of the clip casing, make sure it is nested inside and aligned with the guide collar too.




Step 8:

This is what the completed clip internals will look like.



Test and ensure that the dart pusher is able to move upwards and downwards smoothly.


Step 9:

Create a slot window to view the ammo count.

Use a Dremel to cut out a strip of plastic along the clip casing.




Step 10:

Once everything is ready, re-assemble the clip with epoxy glue (use rubber bands to clamp the casing securely during curing).




Step 11:

Its done!



Check the ammo count by viewing the slot window. :)

--

Loaded in a modded minimized Stampede.



Loaded in a modded brass breeched + shotgun gripped Longshot.