06-15-2017, 12:21 AM
This bugged me a little when I started reloading the Grendel, so here's my interpretation, with no data to back it up.
I suspect Alexander Arms first published their trim lengths to be few thousandths below the chamber neck length of 1.53", which should be a safe recommendation.
I'm guessing Hornady published their initial data after SAAMI specification, when they recommended a length a little below the SAAMI max cartridge case length of 1.52". In the tenth edition, they are showing max case length of 1.52", same as SAAMI. They also recommend a trim to length of 1.51", which is well above SAAMI minimum of 1.50".
How cautious do you want to be? I'd think you're fine keeping the case length a few thousands short of 1.53", thus keeping your neck length as long as is reasonable.
I suspect Alexander Arms first published their trim lengths to be few thousandths below the chamber neck length of 1.53", which should be a safe recommendation.
I'm guessing Hornady published their initial data after SAAMI specification, when they recommended a length a little below the SAAMI max cartridge case length of 1.52". In the tenth edition, they are showing max case length of 1.52", same as SAAMI. They also recommend a trim to length of 1.51", which is well above SAAMI minimum of 1.50".
How cautious do you want to be? I'd think you're fine keeping the case length a few thousands short of 1.53", thus keeping your neck length as long as is reasonable.