Bear Creek Arsenal Complete Uppers

[ported45]

I can't say I'm surprised given that my experience with BCA is limited to one upper, but I am disappointed that you're still having issues with chamber length. Have you shot it at all yet? I wonder because I never saw a need to check the chamber length on my barrel since it was putting out nice groups of Hornady Black from day one, but if yours shoots well with the short chamber, then I may need to rethink that so I'm not unwittingly setting bullets back in the case. I haven't noticed any overpressure signs on casings though.

I never shoot any firearm until I check the chamber dimensions and there is NO way that I would shoot this one as is.

Measure a loaded round, chamber, eject, and measure it again. If it is shorter, you have a big problem like me. If it is not shorter, still check the bullet to see if it is coming in contact with the rifling at all.