Most recent update: 10-25-2025.
Note: Breacher is currently released as an OPEN BETA project. Simply due to the complexity of the blaster, there will inevitably be tweaks and improvements to the design over the coming months.
Note (8-30-2025 11:12PM EST): Hello everyone! I've got pretty much everything up on this Printables page before I head to bed the day before the official launch. Printables is acting up rn and not letting me save some edits to the page (like a better organized layout for the files on Printables), but it's not critical for release. So, the files are out now! Enjoy!
Blaster Overview and Firing Demo:

Picatinny mounted Silly Shell carrier/holder files here: https://www.printables.com/model/1016480
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The Breacher is a 3d printed DIY Nerf-style foam dart blaster, which uses a 3d printable shell (Silly Shells) to hold several darts at once, to fire multiple darts each time you pull the trigger.
Breacher is modeled after pump action shotguns, with a tube magazine that holds 4 to 6 shells (depending on which muzzle tips you have installed). Breacher is able to fire many different types of foam projectile, including Nerf Elite darts, Nerf N1 darts, half darts, Rival balls, Mega, MegaXL, and more.
That all adds up to make Breacher a very fun, and very satisfying shotgun-style blaster!

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A full list of non-US sellers can be found here: https://www.stuffbysilly.com/wheretobuy
Hardware kits are available from these sellers:
OutOfDarts: https://outofdarts.com/products/sillybutts-breacher-hardware-kit
SilverFoxIndustries: https://silverfoxindustries.shop/products/breacher-by-sillybutts-hardware-kit
BearsWares: https://bearswares.shop/products/breacher-by-sillybutts?variant=42277558780017
Fully printed blasters are available from these sellers:
OutOfDarts:
Printed parts and fully assembled blasters: https://outofdarts.com/products/sillybutts-breacher-3d-parts-hardware-kit
SilverFoxIndustries:
Printed parts and fully assembled blasters: https://silverfoxindustries.shop/products/breacher-by-sillybutts
BearsWares:
Printed parts and fully assembled blasters: https://bearswares.shop/products/breacher-by-sillybutts?variant=42277558812785
Additionally, Canadians can get kits here without getting thrashed too much by tariffs: https://1000screws.square.site/product/breacher-hardware-kit-canada-version-/CLBWCGXCTSZHRLV4A7QU3PE5
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Silly Shells are an ecosystem of 3D printed shotgun shells for homemade Nerf-style blasters! There are many, many different shells to use in each blaster, allowing one blaster to fire a wide variety of ammo types without reconfiguration or modding.
For example, you can fire 3 Elite darts out of one shell, eject it, and then load a MegaXL shell to fire a huge dart at your enemies! Then you can follow that up with a “buckshot” round of Rival balls. Then you can load a Bottlenose shell to hit a person across the field from you.
Silly Shells allow you to use multiple different types of foam ammo in one blaster, and they allow you to fire multiple darts with just one shot of the blaster!

Note: Breacher's magazine and feed system does not fit any shells that have ammo sticking out past the tip (full length Mega or MegaXL), however, you CAN still breech load them one at a time into the blaster for single shots.
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Breacher should have the same FPS performance as Battle Axe: https://docs.google.com/spreadsheets/d/1Pixa7pvZfWJ54Cy2VnBE_0UdA56MWYw5ja8P_bJ5XCY/
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Breacher can be customized by mixing and matching the available alternate files:
4 different priming handle options
Default, Slim, SlimGrippy, and Picatinny.
2 sizes of magazine capacity extension tubes, which as super easy to swap!
Alternate files with various sling attachment points on them
Alternate files for printing the longest parts (the priming bars) on a 180x180mm build plate printer. Everything else will fit already!
2 types of magazine follower, for compatibility with several types of drum spring hardware.
Also, there are STEP and F3D source files available for you to customize the blaster even further yourself!
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The correct 3d print files for the follower and follower rollers are determined by which spring you have.
If you have FoamBlast Style drum springs, use the FBdrumSprings files.
If you have generic drum springs, use the GenericDrumSprings files.
Filament usage and print time estimates (PLA filament) (Includes supports and brims for recommended parts):
All parts together: 1962 grams of filament
Green: 1003 grams (be very careful with the green folder prints, or make sure to have 2 spools of the filament on hand in case one runs out!)
Orange: 630 grams
Black: 329 grams

All STLs are exported in their correct print orientations.
There is a .3MF file for Bambu Studio, with all the parts in each folder laid out on plates, in their correct orientation, and with correct infill/wall/support settings.
For brims, make sure you set them to “Outer brim only”, so they only form on the outer edge of the parts. If you have it set to both sides, it will cover up screw holes with brims, which makes it harder to assemble.
180mm x 180mm minimum printer size/build plate size.
The “default” print settings for Breacher are 20% infill, 5 walls (I use Gyroid infill pattern).
Parts with different settings will have those settings marked in bold text.
Black
20% infill, 5 walls: TriggerGuard, GripBody.
20% infill, 5 walls, BRIM: CheekRest_Right, CheekRest_Left, PicatinnyRail_Front, PicatinnyRail_Middle, PicatinnyRail_Back.
10% infill, 5 walls: StockButt.
100% (full) infill, 8 walls, BRIM: PlungerRod.
100% (full) infill, 8 walls, SUPPORTS: PrimingBar_Right, PrimingBar_Left.
Green
20% infill, 5 walls: CatchHolder.
20% infill, 5 walls, BRIM: SideBracket.
10% infill, 5 walls: BarrelFront, BackPTcover, FrontPTcover, StockCap, EjectionPort_Front.
10% infill, 5 walls, SUPPORTS: BarrelBack.
15% infill, 5 walls, SUPPORTS: EjectionPort_Back.
20% infill, 8 walls: GripPanel_Right, GripPanel_Left.
20% infill, 8 walls, SUPPORTS: BoltFace.
Optional: You can also enable ironing on the CatchHolder. Top surfaces ironing.
Orange
20% infill, 5 walls: Trigger, InternalNutCover, LifterRoller, PlungerGuide_Tip, PlungerGuide_Spacer, MagFollower, FollowerRoller, SearArm.
10% infill, 5 walls, SUPPORTS: Muzzle.
15% infill, 5 walls: PrimingGrip.
15% infill, 8 walls: PlungerGuide_Base.
20% infill, 8 walls: Ejector, PlungerHeadB, Extractor, ShellStopLeft, ShellStopRight.
20% infill, 8 walls, SUPPORTS: Catch, Lifter.
100% (full) infill, 8 walls: PlungerHeadA, PlungerCap.
Optional: You can also enable ironing on the Catch, to make it extra smooth. Top surfaces ironing.
Optional parts:
MatchSaver parts all print at 20% infill, 5 walls with SUPPORTS.
The mag tube extensions all print at 20% infill, 5 walls.
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Full hardware list (parts list, bill of materials, whatever you want to call it):
https://docs.google.com/spreadsheets/d/1NP8far9P1kM7TUwjEEXd2ue_4Z4ZWt-sdW7ixpMnTfU/
Make sure you have the correct tab of the Google Sheet selected.
Hardware kits are available from these sellers:
OutOfDarts: https://outofdarts.com/products/sillybutts-breacher-hardware-kit
SilverFoxIndustries: https://silverfoxindustries.shop/products/breacher-by-sillybutts-hardware-kit
BearsWares: https://bearswares.shop/products/breacher-by-sillybutts?variant=42277558780017
I recommend using k25 in Breacher, its what I really designed the blaster around.
Anything weaker than a 788 spring won't do very well with the larger capacity shells (3x elite, 3x rival, MXL, etc).
Springs with strength between k25 and 788 are fine, if you want to use the blaster indoors with younger players for example.
Any springs stronger than k25 don't really increase the performance of Breacher. Stronger springs just make the prime harder, and add more wear and tear to the blaster, without making it fire much harder. K25 is the sweet spot of spring strength.
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Its really good, go download it.
There's really good text and picture instructions for every aspect of assembling the Breacher!
Notes:
Make sure ALL the supports are removed from any parts with supports.
Remember to remove the built in supports from the picatinny rail dovetails.
Put the rubber plunger padding on the plunger face after assembling the plunger rod and two plunger head parts.
Lightly lube the Catch front face.
DONT FORGET the o-rings when you assemble the boltface / plunger cap stuff together!!
- 1 big o-ring on the plunger cap before you glue it to the plunger tube.
- 1 o-ring between the PTcap and the boltface.
- 1 o-ring glued to the front of the boltface.
I recommend wearing gloves while gluing the plunger tube to the PTcap, and while gluing the -016 o-ring to the Boltface.
Round the edges of the plunger tube on the back end so it slides smoothly inside the blaster. Chamfer the inside edge and the outside edge.
The lifter position WILL NEED ADJUSTMENT DURING ASSEMBLY, READ THE ASSEMBLY GUIDE!!!!!

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If you print any of my designs, I'd love to see yours! Please consider leaving a Make on the Printables page, and leaving a review!
Thanks to Wonderboy, Frutiger, Albird, Nomiset, Sakurazaki, Bill, GreyTheColor, Jeef, Piggy, Hotkoin, MetalSuccAttack, and BoomstickMods for photos!
Thank you to all of the people who helped to beta test Breacher! I could not have done this without you, I appreciate it a ton.
Thank you to everyone who left helpful comments and suggested features and fixes for Breacher during it's almost 3 years of pre-release development!
The threads for the magazine tube extensions are Cruller Threads by DonutCat (https://www.printables.com/model/931166-cruller-threads-a-custom-thread-profile), which I adjusted print tolerances for. These threads are REALLY NICE, and I'd highly recommend them to other designers!
The font for the Breacher logo is Falcon Punch.
China: 你好! 我擁有這個設計。 想生產請聯繫我. 你好! 我拥有这个设计。 如果你想生产,请联系我.
Changelog:
8-31-2025: Release
10-25-2025: Added a small file “optional tube spacer” to be placed in front of the magazine tube (so, inside the muzzle) to hold it in place better if the tube is sliding around on your build. Thanks to ChaosBunny and a few others for letting me know this was an issue!
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If you like what I do, please consider supporting me!
I don't charge for my files, so any donations or merch purchases would be greatly appreciated!
Patreon (Monthly donations)
Buy Me A Coffee (One-time donations)
Fourthwall (NEW!) My merch shop! Go get some cool stickers and fun shirts!
RedBubble My old merch shop. It's still there, but Fourthwall makes better stuff IMO.
The author marked this model as their own original creation.