I modifed the mag to clear a unmodifed trunion but the trunion could be ground slightly and mag could be used unmodifed. this will be for a screw build but it wil also allow room for rivets, with the modifed mags. I used a steel mag as I can weld on it if I screw it up. Steel mags are slightly tighter as well so I know aluminum will work down the road. mags are about a dollar for aluminum if you shop around, so modifying them is not a very big deal and they will still fit in a G3 if I had one. these were done with a die grinder but the final ones will be milled so they look much cleaner. this build is abpout working out the bugs.
notice that there is no way that the areas ground away can never make contact with the rounds and the slot I cut will allow room for a rivet or a screw and the rounds wont hit then either. the edge of the mag is the same height as a original. If this was a Saiga with no bullet guide the edge of the mag could be raised and serve as a guide. the edge of the mag does loose some strength but its reinforced by the trunion when in the gun. It could be reinforced by welding a piece of metal across it. but I dont think its nessacary. the rear of the mag may need to be lowered slightly I wont know untill the carrer is in.
Note the differance in a 300 savage VS the 308. I think it will be fine but a spacer could be installed in the rear of the mag.