Full Length sizing my 6.5 Grendel once fired casings

[LRRPF52]

I really prefer the Stoney Point (bought by Hornady) headspace comparator kit.






When setting up my sizing die, I use a stripped bolt to check that my sizing operation is producing cases that will actually fit the chamber.

I size the brass down minimally until I get it to fit in the chamber and allow the bolt to rotate into a locked position in the barrel extension.

You will find that fired cases do not fit in or allow the bolt to rotate into a locked position in battery.

Even partially-sized cases will not allow the bolt to rotate into a locked position, as you have learned the hard way.

The main factor in this is shoulder position. The shoulder must be moved back sufficiently to allow chambering and bolt lock-up.

You also have to factor variations in the brass and processes.

You might make your first few pieces of brass fit fine, but others in the batch will not chamber due to these variances.

Account for that when setting up your headspace.

I do a lot of testing initially with sized cases when dialing in the sizing die, and I also check with completed rounds of ammunition from that batch to ensure consistent chambering and lock-up for the batch.