[Bepe]

I was wondering about headspace after your thread on the initial range testing. It seemed to me that the accuracy was lacking for such a nicely crafted rifle. I was going to post but am not familiar with the accuracy standards of the .264 WM and didn't want to chime in.

Might be a bad case. Might be a headspace problem. I think I'd get a headspace comparator, if you don't have one and do some measuring before firing it again. Hang on to a couple of those fired cases for reference. Measure up some factory ammo also if you have some.

Bepe

 

[Bepe]

Just for kicks I'd get a paper clip and fashion up a head separation tool. Normally when a case is getting ready to separate you will see a white line on the outside of the brass near the base. I don't see any evidence of such on your other brass that did not separate.

Bend a paper clip into a sharp bend and then sharpen the end on a knife stone. You can then reach down inside the case and run the sharpened end up the inside from the bottom. Scraping the inside of the case.. If you are developing a separation the sharp paper clip will catch the ridge.

No disrespect if you already know this info. Trying to help.
Bepe

 

[Bepe]

Hornady makes a good universal tool. I've used it extensively on everything I load. Measure a couple of fired cases and then set back shoulder .001 - .002 when sizing. It prolongs the life of the brass, reducing the need to trim. Adds to safety and enhances accuracy.

I recently bought a dedicated caliber RCBS Precision Micrometer gauge for my 30-06 1903A3. It is superior to the Hornady but limited to only one specific caliber. I don't know if one is made for the .264. If not the Hornady will suffice.

Bepe

 

[Bepe]

What Fire Escape said. Not the end of the world if the rifle does have excessive headspace. You can size your reloads to safely function. Depending on the chamber they may not be able to be used in any other rifle of the same caliber.

Bepe

 

[Bepe]

I had an older 189 series Mini 30 that shot awful. Shotgun splattering on the target with no rhyme or reason. After getting the Hornady Headspace Comparator I discovered why.

A few pictures will explain it. Number 1 is a picture of some Federal 7.62x39mm Factory ammo.

I'll just use the last two numbers from the dial caliper for simplicity. Headspaces at 25.

Next is a photo of a fired case from my newer production 583 series Mini 30.

Headspaces at 31. Recommended maximum headspace is .006 so the Mini 30 is within spec.

Next up is the older 189 series Mini 30. Headspaces at 40.

So .015 headspace from a factory Federal case. Not a big deal on the low pressure 7.62x39mm round. Factor in the pressures on the Magnum and easily could blow a case.

Bepe