I had a partial case head separation using a 1.8oz buffer

[LRRPF52]

I wonder if the Grendel is unusually sensitive to this issue. WAY back when the issue of Quickload predicting overly high pressure for the Grendel was first raised, a plausible explanation was that on this cartridge, the base of the bullet is so close to the primer that the ignition of the primer started the bullet moving. This resulted in a larger effective case capacity before much of the powder had started to burn. If the bullet is pinched in place by the neck hitting the beginning of the freebore, the pressure increase would be even greater (combination of smaller case capacity and higher bullet clamping pressure).

Fun fact: I have never had Lapua brass reach the 1.530” case length from stretching that I’m aware of.

I have had older PPU brass exceed that length even from a single firing.

Generally, chambers are cut with additional neck length, but you really have to watch for it with softer brass in lower pressures, and any brass run at higher pressures.

My .260 Rem brass needs trimming, otherwise I can’t load it.

A lot of .308 Winchester once-fired I have needs trimming.

My Lapua and Hornady Grendel brass....I have never trimmed. The most case length I get to is typically 1.5260” or a bit less.