MDT makes an AICS mag that should work, the round seems to fit in the Bighorn Origin action ... not a lot of room to spare but it fits ... please share what success or problems you've had doing this.
I have a zermatt Origin s/a chambered in 6.5prc, it was giving me feeding issues at first so I had a friend notch the feed ramp on his mill and ever since it has ran perfectly!
A buddy of mine also notched his as well to run 6.5prc to improve feeding reliability.
Edit: I am also running the MDT aics short mag magazines with great success!
Just received my barrel last week from another member on here, Bartlein. I torqued it on an impact SA in an MPA chassis. While i haven't had chance to shoot it yet, just cycling it with ammo it feeds fine. Only thing is, the loaded ammo is not ejecting properly. I ran some empty casings thru it and it ejects fine. I'll see what happens when i shoot it