Airsoft Impact Spring Grenade

The objective of this project was not to out perform the commercially available spring grenades, let alone the gas ones. It was mainly to test the concept and make a working airsoft spring grenade that doesn't use trap doors.

That said, I'm happy with the results and excited to share with you.

You can follow this video below for specs, know how it works and assemble the grenade.

The performance of the grenade is heavily linked to the springs, I wouldn't go higher than 50mm for the AEG spring (I used a stock one) because I see no real benefit for it.
As for the trapezoidal (mid cap) springs, the best quality you can find, the better. I used the springs from a Cyma mid cap 140bb mag but I believe Maple Leaf sells a "better" spring kit for mid-caps for around 15€ so if you are going to invest, you may want to consider in that possibility. If you end up using the Maple Leaf ones or any possible better springs, please do let me know.
As for the 4mm pen springs, as long as it's around 4mm in diameter and compresses enough for the traps to compress and let the BBs through, it should be good.

Hardware needed:
- 1 AEG Spring (or similar) cut to 40-50mm (length will depend on your spring strengh)
- 1 Mid-cap (140bbs) or 1 trapezoidal spring cut to 6 sections of 90mm
- 2 4mm pen springs cut to 6 sections of 4-5mm (don't use the ends, it might not compress enough=
- 13 M2x8 bolts (M2x6 can also work but I'd rather use the x8)
- 1 1.5mm allen key to be used as a pin or anything you want to use instead

I've given 0.3mm tolerance overall between parts but sanding might be needed for optimal performance. You want the BB to go through smoothly and every part to slide well. All that while not having a huge play between parts either.

The skin (printed in TPU) is optional but highly recommended for durability, knowing this is something you'll be throwing around. If something is to break in the interior, it's more likely to be the piston shaft due to the middle section thickness, so this is one of the reasons why I wouldn't over do the spring length, more length means more power but it also means more stress, and in this case, more power wouldn't give you better results.

The skin also serves an aesthetic purpose, so I'd like to have more variety in the future.
If you have a design in mind and can't model it, send me some sketches with the precise idea (possibly with precise dimensions too) and I'll be happy for model and join it to the STLs.

Leave your feedback and questions in the comments.

Fire in the hole!