Hello AR enthusiasts, I am building an AR with a 18" SS barrel chambered in .223 Wylde. My question is what caliber headspace gauge do you think I should use to check the fit after I insert the bolt? Would .223 suffice?
The upper was bought used off of gunbroker. I am pretty sure someone put this together themselves. Since I am putting a new BCG in it I just want to 2x check its gonna fit right.