R P Brass
Full Metal Jacket--i second Walkalong's post re. R P brass being on the thin side. As BTP pointed out, the .45 ACP round is a low-pressure affair, so it's not as critical as it might be.
If you can resize the brass, and taper-crimp it to hold the bullets (I use lead bullets, for bullseye shooting; that's where my experience with the .45 lies) it should work just fine.
You've already got the R P brass so price is not a consideration @ this point. I'd not pay $$ for any more of the stuff, though. (I never pay for .45 ACP brass--I have enough free range pick-ups.)
Frankly my supply is large enough that I'm gradually culling the R P brass specifically because of the thinness--with bullseye shooting you want everything as completely equal, shot to shot, as you can possibly manage. But I'm still loading everything else, except of course steel, Al, and Amerc brass.
Keep an eye out @ the range; scrounge whatever you can, and soon you'll have a nice collection of Win, Fed, Fiocci, Speer, and Starline .45 brass, and you'll see that all of that has thicker walls than the R P stuff.
Somebody on one of these gun-users' fora did a study on brass longevity a while back. IIRC, the R P brass lasted for several reloadings before the lot began splitting, wheras everything else lasted for more reloadings. I'm sure the thin R P walls were a contributing factor.