[imarangemaster]

Here is a thread I did over 5 years ago (dang, it doesn't seem that long ago) about the best way to fit a 30 round USGI aluminum mag in the stock. When I brought up the old post, I was surprised that my second SU-16 was a CA model, not a Bravo like my first one. BTW, having used both, I now prefer the longer sight radius of the A & B.

Hope this helps:

http://www.thektog.org/forum/f88/30-round-magazine-stock-update-easy-1-2-3-a-225312/