I used to own a VEPR in 308 and made it take m14 mags by drilling a hole in the trunion at the bottom to install a pin made out of steel rod to serve as the front pin for the mag to hook into. I then welded it in place. I then had to make a new mag release (easy) to hook correctly on the mag catch on the backof the mag. Finally the reciever had to be opened up, just a hair, for the mag to fit. It ran great. Granted the Saiga and VEPR are a little different, but I bet a similar technique might work. The hard part is making that first decision to cut on your gun and possibly turn it into a paperweight. I think there are some small outfits doing these mods. Possibly Krebs Custom or Tromix. Good luck-John