Prototype NERF MA40 Mag concept


New Member
Hello Spartans,

I'm new to the 405th but I thought I would share my recent fun with the NERF MA40. Currently I am prototyping MA40 Mag cover to go onto 10 or 12 dart NERF mags so the prop can have spare mags when using the blaster. This is my first 3D model that I have sketched in Fusion 360 and the V1 is printing as I type, but I thought I would share my concept and eventually the files once it works (hopefully).

I also made a template to print our a ammo counter onto a transparent sheet so anyone can put a light in the NERF counter. The PDF template prints in A4 and has 10, 32 and 60 as the numbers. I used clear blue film and a cut out of an LCD screen diffuser film from an old laptop in my mine.

Hopefully I have posted these in the right place and that they will be helpful people as it has been a fun learning curve for me. Once it has printed successfully (fingers crossed) I will share my results.

MessiahLad 027

V1 Mag adapter.PNG

V1 Mag adapter well.PNG

NERF Ammo Counter
led counter.jpg

I have CR2032 battery inside it and a small switch on the side, which my son loves and steals it for his NERF guns as well.


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  • AC MA40 Template Multi number publish.pdf
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New Member
Can you share more details on the ammo counter? That looks awesome and I would love to do something similar to mine.
Absolutely, I when I get home tonight I'll take some pics and make some notes as it is a very easy mod. Once the transparency is done, you just cut it to fit inside the counter window.

But the parts list is as simple as a CR2032 battery and holder, a 5 mm blue LED which works fine at 3v, a tactile latching switch, some blue film or even better some blue transparency and then something to diffuse the light to make it even. I used the film that came from an old LCD monitor (laptop in this case) removed it from between the LCD panel and the backlight, but you can us baking paper instead, but LED diffuser works really well.

One thing I needed to do is trim the plastic which the clear window is held in by as it blocks some of the light, so trimming it to just the corners made it look better. For the next build though I might try to print a battery, switch and LED bracket as a single piece to make it easier becuase you can get a better switch design that way, more hidden.


New Member
Before leaving for work this morning I checked the printing but unfortunately the PTFE coupler had let go, releasing the tube and filament during the night, so I have a failed print but it was enough to show that the model has promise. The test fit seemed good, but screw holes could be wider. I will know in another 12 hours if the next print finishes if the prototype is a success. When it is finalised, I will share it here. For a first sketch, I am really happy with how it has came to life.