Woops I jacked up my barrel

[woohoo]

Can you be more specific about exactly what brand and model of tools you prefer for barrel installation? That step is important (and intimidating) enough that it has made me shy of doing my own builds.

barrel extension socket-https://encrypted-tbn2.gstatic.com/image...VqttjTAi4a

If you use a hand torque wrench like a snapon you will have a hard time holding the barrel from rotating. Any 1/2-3/4" air driven impact that will hit 150ft lbs will rattle the extension on and get it much tighter than a hand turned wrench.

The round part vise I use weighs about 40lbs and runs around $200. Rosin on the round alum jaws will help hold the barrel still in a normal vise.

You can't change the headspace unless you have a reamer or a lathe. It is what it is. The only thing you can do is check and change bolts to one that matches better.