In search of...

[Creedmoor]

I miss read.
The last one I did I cut a piece of white oak and slid it in the mag well.

 

[ditcherman]

This thread is a little dated, but many of the responses are tapping around my question, in response to the OP.

Looks like I may be helping someone assemble an AR.

I've assembled a lower, but not an upper.

What have you used in applying torque to the barrel nut if you did not have an action bar, or one of the plastic clamshell upper holders?

I don't want to mar or twist his shiny new Aero upper applying the barrel nut torque.

Looking for ideas.

IIRC I have used a junk lower, pinned to the upper, with the junk lower in a vise, or on a mag holder.

This only works if you have an idiot friend who lost track of where the mill was and went right through the bottom of my his lower.
It could put some serious stress on the pins and break something there if not careful.

I have a cheap clamshell holder and it always seems like it leaves some marks.

 

[edwea]

These are pretty cheap ($40ish) and work well. And if you're applying heat to the receiver you don't need to worry about melting plastic.