New to 40mm and haven't been able to find any information online about this.

Could you legally 3D print a nose cone for a 40mm that would accept a glued in 50bmg spotter tracer round for use in an M203 so that there is a pop/flash upon impact? Would there even be enough velocity from a 40mm to detonate?

Legally, yes.

Would it work? Probably not. Likely too little velocity.

Even the 14.5mm artillery sims that we use, tend to add too much weight to the pusher and slow the velocity too much. That's why we 3d print the whole projectile and then add the 14.5 projectile. Some have also machined lightweight aluminum pushers to hold the 14.5 projectiles.

The 50bmg spotter projos are designed to go a lot faster than 250-300fps. Not as fast as 50bmg (since they are 50-spotter) but still multiple times faster than an m203 round.

Maybe I'll pick some up and try it. But I wouldn't expect it to work well, maybe if your shooting at boulders or big steel plates

Thats pretty much on par with my thoughts. Was going to look at 3D printing the entire projectile with a hole for the 50cal projectile to insert. I've got a guy locally that is selling a bag relatively cheap. Thought about picking them up for science. Worst case scenario is they don't work and I give them to a buddy with a .50bmg.

Tag.

I load BMG, and thought about picking up some spares to try in 40mm. But as mentioned, the velocity is significantly lower. I'm guessing a nose on hit with a solid target might work, but anything shy of that probably won't work.

Maybe I'll do some testing as well.

Google isn't turning anything up... I'm guessing this is a design in which the nose cone would need to impact and cave in enough to have a pin hit the primer?

Been looking for a STL file for a setback safety fuze design.  Anyone have one?

Im currently working on one. Im narrowing down issues, but its the rainy season in the PNW so the days I can get out to test are limited. Tomorrow I have four varients Im going to send.