Georgia Arms offers the loaded .45 Auto Rim in both inexpensive lead and a good hollowpoint load. This is first class ammunition! Also, you can reload .45 ar brass in .45 acp dies by simply purchasing a .45 AR shell holder. Also, Starline brass makes the brass. You are in business! These guns are very accurate. About 20 years ago Dave Andrews of Speer published a great number of loads on this caliber, and he used his for a deer gun. Moderate range, heavy bullet. I would stay with the 230 gr. modeate loads in this type of gun. Also, lead bullets usually shoot just fine. Try GA they will help and mention bob campbell sent you.
If you really have a problem finding this ammo give me a e mail and I may scrounge some up for you locally.
regards
rkc