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Finding an AR's headspace without gauges

Fatelvis

Sergeant
Full Member
Minuteman
Jun 15, 2003
304
4
Mokena, IL
Can a once fired piece of brass from an AR be considered a good depiction of what the chamber's dimension's look like? I'm used to working with a M1A, where you need to shut off the gas system to reliably trust your brass's measurements. I have been using a headspace gauge to set my sizing up until now. Thanks-
 
This ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ An easy way to do this is to F/L resize 2-3 cases and make dummy rounds (bullet seated with no primer or powder) and chamber them in your rifle. Adjust your die and set it where you find the dummy rounds chamber and then extract easily. It is easy to do without a gauge, however, using a gauge is a better way to do this since a gauge will show precisely where the die has to be adjusted to the proper shoulder bump.

I reload for about 8 308 Winchester rifles and for about 6 .223 / 5.56 chambered AR-15 rifles, for me, bump gauges make adjusting shoulder bump much easier.

AR-15 type rifles will tell you right away if your cases aren't sized /bumped enough. The extraction of the cases will be very difficult to extract out of the chamber.
 
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