Thread: Neck sizing for AR-15 platform

Neck sizing = stuck cases. If you want to size the neck without over working it, better concentricity etc, you can use a FL bushing die, you will just have to go for tighter neck tension than you would with a bolt gun. I think 4 thou is the recommendation. You need to bump the shoulder of
the case between 2 and 4 thou and size the body well for reliable function in a semi.