Let me preface this by saying that I have a .264LBC barrel from Black Hole Weaponry with their matching bolt in my AR. I worked up some loads using new Hornday brass, 120 grain A-Max bullets (that weight is what I could find when I started shopping for bullets, so I have a bunch of them) and 8208XBR powder this weekend, starting with 27 grains and working up in half-grain increments to 28.5, five rounds per load. I set up my bench, bags, etc. and set a Birchwood Casey Shoot-n-see target with five diamonds on it at 100 yards and commenced firing.
Five round slow fire with 27 grains of 8208 yielded 1.1" for four shots with a called flyer outside of that. Let the barrel cool.
Five rounds of 27.5 grains yielded .88" for four shots with a called flyer outside of that. Let the barrel cool.
Five rounds of 28 grains was sheer ugliness at 2+". Let the barrel cool.
Five rounds of 28.5 grains was even uglier, 3+". Let the barrel cool.
For giggles I decided to sling five rounds of factory Hornady 123 grain A-max at the remaining diamond on the target and got another 3+" group. Considering that the 123 grain A-max factory load is the gold standard for the Grendel round, I thought that was a bit unusual but it's not the first time it's happened with this rifle. It apparently doesn't like the taste of the factory loads.
I've loaded up ten more rounds of the 27.5 grain loads to check one more time, but if that one looks as good the second time around as it did the first time, I guess I'm stuck loading my own. Darn...
Five round slow fire with 27 grains of 8208 yielded 1.1" for four shots with a called flyer outside of that. Let the barrel cool.
Five rounds of 27.5 grains yielded .88" for four shots with a called flyer outside of that. Let the barrel cool.
Five rounds of 28 grains was sheer ugliness at 2+". Let the barrel cool.
Five rounds of 28.5 grains was even uglier, 3+". Let the barrel cool.
For giggles I decided to sling five rounds of factory Hornady 123 grain A-max at the remaining diamond on the target and got another 3+" group. Considering that the 123 grain A-max factory load is the gold standard for the Grendel round, I thought that was a bit unusual but it's not the first time it's happened with this rifle. It apparently doesn't like the taste of the factory loads.
I've loaded up ten more rounds of the 27.5 grain loads to check one more time, but if that one looks as good the second time around as it did the first time, I guess I'm stuck loading my own. Darn...
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