Originally Posted by 69Mach1
Pressing on the barrel items:
Start with alignment. I use the rear sight base pin sticking out perpendicular from the base to match up to a bit I placed into the groove in the barrel for the RSB pin. Once it's very close, I'll start to install the rear sight block onto the barrel.
Using my press and an AR 15 multi-tool (you read right) I will secure the rear sight block and press the barrel onto the RSB. I'm protecting the chamber end of course. Hopefully everything lines up and the pin will just go in.
Using the AR 15 multi-tool again, I'll press the barrel onto the gas block.
Finally, while securing the barrel, I'll use a socket with an inside diameter that's larger than the barrel muzzle, I'll press the front sight base onto the barrel.
If you get lucky, at least one of the two pins in both the gas block and the front sight base fits. That way both are secured onto the barrel so that they don't move while you ream the other hole to fit the second pin.
I do not see where you did a Go, No-Go check. I'm assuming the only way to establish the correct headspace is to keep pressing in tiny increments (how precise are the garden variety 20 ton presses in moving the barrel in hundredths of an inch when you get close?). I suppose the only way to fix too little head space is uglier - bash it out with a hammer and block and start over?
If there is any aspect of the build that worries me, it's the amount of time and effort in moving the barrel in tiny increments - testing and moving a little more. Sounds nerve racking. At a build party, I'm betting the press is in high demand - how long does it take on average to get the barrel pressed, tested and adjusted per build? How many have to start from scratch because they overshot the head space?