Gunsmithing How much do you open barrel breech for PTG R700 magnum bolt for the AR15 type extractor?

[Clark]

The extractor will not snap over the case rim when the bolt head is down in a 0.700" hole.

 

[Danny1788]

I usually cut the counterbore .720", usually .715" will work but just to be sure I open them up to .720" with a boring bar.

 

[Clark]

I was calculating and measuring and thought 0.717" was going to work. It did not. I just kept boring out 0.002" at a time until it worked at 0.731".