Is Olympic the only game in town for 45 ACP uppers for AR15's ? From what I've seen it appears that you can't buy the necessary parts separate to build your own.
I was thinking about buying (or assembling) one to use along side of my 1911 but I don't know what to expect from a carbine length barrel (14 1/2" to 16") regarding reliability and function using 230 grain ball ammo as a minimum loading. I don't know if the type powder would be an issue.
One last thing. The Pros and Cons of it.........