I have not seen any available yet from Hornady. An the idea of a short magnum in a AR style is interesting I just don't know enough about the AR platform to say much about it. It may give some issues with the short fat round feeding. As for bullets coming apart that would depend on speed being pushed and type of bullets being used. I know I have used 52 Gr Sierra HPBT and 55 Gr Nosler Ballistic tips both pushing 3800 FPS and I did not see any problems but my twist is 1:10. Good luck