For your amusement…
My Frankenstein platform. A G21 converted to about anything you can think of. Here in a 6” 9mm Luger using a 11# recoil spring, G20 conversion barrel, and a cheap optic mount I found. I’d not try it on heavier recoiling applications but it seems fine here. Usually very reliable using 10mm mags for the 9x19. Using 115 gr. an occasional failure to feed, 124’s are better for practice. I like shooting 147/158 gr. at 1000-1100 fps, they work great. The barrel is conventional rifling so ok. Just for cheap fun and gong ringing. I’ve modded the trigger system but would like to try a Timminy. I have barrels in .45/.460, 10/.40, this 9, and I’m poised to play with .357 as well. I’ve done much the same with my G23, using it in 9mm and .357, but no optics. With conventional rifled barrels cast bullet shooting is great. Toolish but resilient and rife with aftermarket fun.