The cheapest stuff I shoot is Estate 1 1/8 oz #6 and #7 1/2 low brass. It hasn't had any issues with them. Haven't tried any 7/8 oz loads in it.
With my VEPR and the Saiga I had before (especially the saiga) I decided to avoid loads less than 1 1/8 oz. They would short cycle my saiga about once every mag, even after a bunch of parts and polishing. It was easier to get better shells than to open up the gas port.
They have a few new models since I got mine:
Marine with 18 1/2" bbl and sights:
1301 Tactical Marine (beretta.com)
Pro model with a blue reciever and recoil absorbing stock:
1301 Comp Pro (beretta.com)