GP-30 M203 Hybrid

my (so far failed attempt) to make a hybrid mix of (airsoft) gp-30 & m203 grenade launchers

list of known & possible problems:

1. frame attachment to barrel rail may be too weak and could possibly break, (there is defiantly some flexing)
2. tube may or may not be the wrong calibre, i don't actually own any shells to know for sure.
3. the hammer may be too weak to activate the grenade's release valve due to it's short travel length (but it may be possible to attach something to the top of the hammer to make it hit harder)
4. the shell extractor is located on the same side as the tube lock, this is a possible problem because that also means the shell is only getting held in place on one side, so the underside of the tube may flex apart apon fireing (if it even fires that is), but however if it was on the bottom then there would be the possibility of it not letting the shells fall out due to the shorter than normall opening length (front of shell not clearing the back edge of the tube due to the extactor holding up the back end of the shell).
5. the screws are a random mix of m3 m2/m1.8 and glasses repair kit (i think M0.8 or m1.2) so getting them all is a bit annoying.
6. i don't have any springs so i'm not sure whats needed there.