I have several 62TSX's for the 223AI. I have no 75S2's....nor have I done the mag box modification yet. That's my next project for the AI. I do have several of the 75A-Max's to play with.

Having never shot either 75 from the 223AI, I'm guessing the velocity/pressure edge goes to the A-Max because of bearing surface. What's the real world velocity difference between the two?

I know I'm not guessing that you've tried both. You chose the A-Max for a reason.....

I enjoy handguns and I really like shotguns,...but I love rifles!