Python - Mag-fed Pump Action Nerf Blaster

Intro

Python is my take on a Nerf pump action springer. I spent a lot of time making the blaster as easy to build as possible and giving it as many quality-of-life features that I could think of. So, I hope you enjoy what I have made and have a blast with it. Let me know if there's any new features you would like to see added to it.

Features 

• Smooth ball bearing prime. 85mm Prime Length
• Magnets to keep the bolt closed. 
• Metal reinforced buffer tube. Compatible with M4/AR-15 Stocks 
• Compatible with a range of springs. Designed to work around worker harrier springs. 
• Spacers to tune the FPS. 
• Barrel cover. Which is design to fit a Bcar inside. 
• Compatible with most talon style mags. 
• Skinny breach for mag drops. 
• Plunger catch with a ball bearing for a lighter trigger pull. 
• One screw to quick change the spring.

Performance 

There is also a longer barrel version available which has a longer front barrel to accommodate a 320mm barrel. FPS numbers on the longer barrel will be uploaded soon. 

FPS data on 1g and 1.2g worker HE darts:  https://docs.google.com/spreadsheets/d/1vmOYlO9HM4aXdmFJTE5ybMgm97uYCdOruBWJxby5j6I/edit?usp=sharing

Hardware 

Full hardware list: https://docs.google.com/spreadsheets/d/1PNj7xVKQFLxMlUX7ag9tBGzUFvliUOoXw0jgVZqwEXI/edit?usp=sharing

Metal tube drawings:
https://drive.google.com/file/d/1f0EPDJA7ELuGQB9Fe3WEfvO76etb0iSg/view?usp=sharing

Priming bar drawings: 
https://drive.google.com/file/d/1ocjbx63nUMUVVN-Q-FpFRlm7HIP-MqUk/view?usp=sharing

Sellers

Hardware kits:

• Contact PotatoFeederNerf for there Metric Hardware kit on:
  - Printables: https://www.printables.com/@PFNerf_2260937
  - Discord: waff2110
  - Reddit: https://www.reddit.com/user/PotatoFeeder/

Alt Parts 

Some parts have alternative versions. Which are different designs that can have different features. For example, one of the alternative versions of the front barrel is the long front barrel. This allows for a longer barrel and Higher FPS. Any part with an Alt version will have a file named after the part with all the alt versions inside. 

There is also Tolerance versions of parts. These will have a file just like the alt version do. These files will contain different tolerance for the same part. The buffer tube is one of the parts with tolerance versions. These are different versions that except different sized metal tubes. 

Print Info 

All the stl and 3mf files have the correct printing orientation. 

Filament usage: 

PLA ~ 1230g 

TPU ~ 1.5g 

Everything is in PLA other than the “Plunger Padding” which is printed in TPU. I used 95A but other types can be used just increase the infill if you're using a softer TPU. The Plunger padding isn't required but highly recommend as it help a lot with dry firing. If you can't make the plunger padding. Either pad the plunger with some adhesive rubber pad or try not to dry fire if you have nothing on the plunger. 

Print settings 

The 3mf files have the optimum printing settings. They also include body modifiers to optimise strength and weight. Not needed but highly recommend.  

Use the 3mf files if you can. If not here are the recommend print settings for the stl files. 

Main Parts file: 

• All Pump grip variants: 6 walls, 30% Cubic infill 
• Picatinny rails: 10 walls, 30% Cubic infill 
• Trigger: 8 walls, 30% Cubic infill 
• Left and right Priming Spacers: 15 walls, 30% Cubic infill 
• Mag Catch: 6 walls, 25% Cubic infill 
• Plunger Catch: 16 walls, 25% Cubic infill, 0.12mm Layer height 
• Buffer Tube: 6 walls, 25% Cubic infill 
• Front barrels: 5 walls, 25% Cubic infill 

Bcar file: 

• Python Bcar: 5 walls, 25% Cubic infill 

Angle Grip files: 

• Python Picatinny Angle Grip: 5 walls, 25% Cubic infill, 0.12mm Layer height 
• Slide Lock: 12 walls, 25% Cubic infill 

Plungers file: 

• Plunger: 10 walls, 25% Cubic infill 
• Plunger ram: 5 walls, 25% Cubic infill 
• Plunger Padding (Printed in TPU): 1 wall, 10% Gyroid infill 

Spacers file: 

• Spacer: 7 walls, 25% Cubic infill 

Stock File: 

• Stock: 4 walls, 25% Cubic infill 
• Sling Loop: 6 walls, 25% Cubic infill

Everything else that's not mentioned is printed with 3 walls, 25% Cubic infill. If a layer height was not specified, then 0.2mm is recommend. 0.12mm for everything also works fine if want smother angles on some of parts like the stock and the main shell. 

Assembly 

Assembly video: https://youtu.be/DR9qiElz62Y?si=mVFD1DWRbPUW4lFS

 

Changelog

21/08/2025:

• Changed M3 Screw hole sizes from 3.5mm to 3.2mm to give the screw heads more contact area.
• Decrease M3 Heat inserts hole size slightly.
• Decrease M3 Threaded hole size to give more bite on the screws.

05/08/2025:

• Added PotatoFeederNerf Metric Files.
• Added metric hardware to the hardware list.

29/07/2025:

• Added STEP File of the full blaster assembly.
• Added 3mf File of the original blaster configuration assembly.
• Change the name of “Short Plunger” to “Plunger” in the stl and 3mf files.

24/07/2025:

• Shrunk the heat set insert hole on the plunger to work better with M4, 6mm OD heat set inserts.