Squaring & Lapping the Upper Face

[explorecaves]

Ted - I'd read about that barrel nut tool in a previous thread. How do you approach aligning the gas tube, when using the tool? I'm curious, since the upper is facing down.

I like the idea of avoiding applying any torque to the upper receiver, regardless.

You can mount a socket breaker bar in the vice and then have the extension tool just outside the vice pointed up. Voila! The upper is now facing up so you can see the gas tube alignment.