I was having feed issues with my Velocity uppers and the curved Sten mags included with the DB9 Alloy, the stripper wasn't making enough contact to reliably feed. So I put this mag together and it has performed flawlessly for me so far but I need a bigger sample size to be sure. Biggest concern is the tolerances being too tight for this to work universally.

New Feed Path
Entire mag raised 1.5mm
Feed lips slightly altered
Beefier Base plate and locking mechanism
Thickened things up a bit to get rid of mag wobble

I'd suggest printing just the top section first to test fit before printing the whole thing. It might be too tight for other uppers, but if it works, it will run great for you.

You'll need a long glock mag spring, instructions shouldn't be needed. Print with 2A settings, insert spring, shoot gun.

I used a few sections from DurbanPoisionPew's excellent Sten mag remix that can be found here. https://odysee.com/@DurbanPoisonPew:9/Curved-Sten-Remix:b