Re: 6x45 barrel options.
I think Hart will make you an AR barrel in 6x45. I just ordered a .224 1 in 8 AR HB blank, to thread for the extension, chamber, crown, and put the gas port in. I think Karen told me 12 week lead time. Check their web site for the varing degrees of AR barrels. A good custom barrel, like the Hart, will eliminate the barrel as an accuracy 'robber', where you can the concentrate on upper to lower fit and trigger,,,, and most of all the 'nut behind the trigger'. I've custom barreled several ARs, from blanks, and always been satisfied with the results. They make an excellent, fast handling coyote rifle as long as you watch the weight of the completed rifle. It's a bit of a different deal than fitting a barrel to a bolt gun. Definately a bit more 'involved'.
"Shoots real good!": definition; it didn't blow-up in my face. 1993 graduate Montgomery Community College 2yr. gunsmithing program