Warhammer 40k Nerf Gun Mod

As a fan of Warhammer 40k, I have always wanted a Bolt Gun.

There are a few 3D print STL files out there, but they are all “non-working” props. I really wanted a Nerf Gun style that would “shoot bolts”.

I have minimal 3D design skills, so I used Tinkercad to design & create the STL files as it is easy to use.

Designing a full working Nerf gun from scratch is beyond my skill, so I looked to create a covering to encase an actual Nerf gun to get the appearance I wanted.

Nerf Gun

Filament : I used Prusa PETG

5nr. M4 55mm Bolt with Nut

Paint Primer / Paints / Varnish

Standard superglue

Leather strip for grip

Printable transparent stickers

Sand paper

Equipment

3D Filament Printer (or access to one)

3D Software – I used Tinkercad

Dremel or files

3D Printing Notes

I printed in 0.2mm layers with a 0.4mm nozzle

The thin decorative panels I did 100% infill. For the spacer plates and scope I used 25% hex infill pattern.

I am not an expert designer: there are probably better settings to use, but these worked for me.

First up I needed to work out how to attach the printed parts to the Nerf gun.

The Strongarm Nerf gun has a rail on the top to allow for attaching accessories. I needed a simple block that slid on the top mount rail, which then had holes to take bolts for attaching other parts.

After measuring the gun, I designed the block in Tinkercad and a with few trial prints (of sections only 10mm long) I arrived at a final design.

To make it fit the gun I had to trim the existing gun sight and remove a moulding line. For this I used my Dremel & files.

The end of the rail block is flush with the end of the barrel.

From this rail I could then hang the side panels.

As I wanted to enclose the dart cylinder, I needed to build-up the side to be able to put a flat decorative plate on it.

I measured the Nerf gun, sketched out the dimensions and decided how I much I needed to cover it. I returned to Tinkercad and designed a side panel.

The purpose of this panel is to bring up the height of the frame around the dart cylinder.

Once I had a design in Tinkercad, I did test prints on the 3d Printer to refine the sizing and shape. The test prints were only 1mm thick. The final print was 11.5mm.

The top of this infill section has holes to take the bolts and a recess to take the nut, to enable connection to the rail block.

Next is a decorative panel to cover the right side.

I wanted to hide the bolt nuts, so this decorative panel covers them and is glued to the spacer section.

The decorative panel is 3 mm thick. I used accents and embellishments found on Thingiverse to thematically fit the "40K" universe.

Fleur-De-Lis Skull: by AndreasFjordsoeJorgensen (Link)

Flying Skull: by Peachpunk (Link)

Banner: by Kresty (Link)

Aquila: By Vsaari (Link)

The left side had to remain partially open to allow for the loading of the darts

Using the outline of the right hand design I measured the Nerf gun for the cut out area.

More 1mm trial prints were done to get the correct size.

The accent here is a modified form of the Fleur-De-Lis Skull used on the Right Hand Decorative Panel.

The bottom section was designed to be glued between the 2 side plates giving rigidity to the shape.

This is also where I added the appearance of a ammo magazine in my Tinkercad design.

The front & top plates were again designed to be glued to the gun.

To check the alignment of the hole for the Nerf gun barrel, 1mm think test prints were used to get the sizing perfect.

The scope is a modified Thingiverse model, the original is by anthonyv1 (link)

Using lots of sticky tape, I did a trial assembly to make sure all the parts fitted together.

As I wanted to paint the entire piece, I took apart the Nerf gun – when doing this make note of where the screws & springs go (there are so many).

I also filed / sanded off any logos / writing that I did not want in the final model.

As smooth plastic & PETG filament do not take paint well, I used a primer and sprayed all the printed and original Nerf gun parts black.

I used acrylic paint applied by airbrush. Alternatively a suitable spray can paint would also work.(Tip : Ensure the area is well-ventilated).

Then I did the final assembly, consisting of :

1. Rebuild the Nerf gun.

2. Glue top rail mount in to position.

3. Bolt the Right Hand Side Spacer Panel and the Left Hand Side Panel in to place.

4. Glue in the Bottom Spacer in to position.

5. Glue in to position Right Hand Side Decorative Panel and the Front Panel.

6. Glue in to position the Top Panel and Scope.

There was a gap between the 3D-printed plates and the Nerf gun in the slider and trigger areas. I filled these with modelling putty. (Milliput)

Using acrylic paint I then dry-brushed the metal effect and painted the embellishments.

Once the paint had dried, I used a spray can matt finish varnish. (In a well ventilated area).

A leather strap was wrapped around the grip and I printed stickers to give a “model and serial number”. A marker pen (Sharpie) was used to draw in a range finder on the scope.

And now I have a “fully working bolt gun”.

I hope my project inspires you to convert your Nerf gun, for whatever style you want as the principle could be the same for any Nerf gun with a top rail mount.

If you have a Nerf Strongarm, I have added the .STL files you need to replicate my project.

Feel free to use & amend the project STL's as you wish for personal non-commercial reasons only.

Disclaimer : I do not own the IP to Warhammer 40k (Copyright belongs to Games Workshop).