I do not believe the AI mag will allow you enough length to have decent case capacity. I use Alpha II mags which will allow an oal of 2.95". It has been so long since I have loaded for my 7rsaum I can not remember the oal. As far as using a S.A. you may have to pull the bolt more then likely to extract a live round.
"I, however, view ethics as an individual decision. My ethics are mine - and I won't explain or justify them to anyone else. I seek nobody's approval, just that of my own conscience. "
With the chamber I have my OAL is 2.9", I have the Wyatts extended box in my rifle w/ a Stiller Tac 30 opened up. Extremely accurate rifle. Velocity who cares, accuracy is where it counts for me anyway