mac37 Wrote:I'm new to the Grendel. I just bought a Specialized Dynamics 20" .264 LBC upper. I was lead to the LBC because I was told it would shoot both Grendel and 264 ammo.
Mac:
Normally a guy needs to bump fired brass in order to get it to chamber. Since you are shooting factory loads, I doubt the problem involves the Lapua / AA or Wolf brass.
Note that the all Hornady does with their brass is to change the headstamp between Grendel and .264 LBC. Just like you can buy Grendel brass with Lapua or Alexander Arms headstamps. The brass is identical in dimensions.
The first run of Grendel brass that Hornady made had problems chambering in AA chambers because the brass was too long. Just like your current situation as you have found by measuring.
Maybe who ever made your barrel cut the chamber long to accommodate this first run of Hornady brass? If they did, it is possible -- although I believe only very slightly -- that your AA and Wolf brass is so short that you are having problems with the firing pin hitting the primer hard enough to set it off.
I say this because I have deliberately fired Grendel ammunition through chambers cut for the 7.62 X 39 brass while using the Grendel bolt -- thus creating excessive headspace. All rounds fired. Also, I have fired .308 ammunition out of 30-06 chambered rifles without any problems other than destroying the brass.
Some of us never had a problem with this first run of Hornady brass but enough others did to make Hornady take note and subsequent lots of their brass has not shown any problems that have been brought to the attention of the Forum.
Les Bear and Hornady both state very clearly that .264 LBC is interchangeable with Grendel brass.
LR55