Nosler 300 RUM brass

[blacktimber]

I have been shooting 300 RUM with rem brass for several months working on load development and accuracy. Using 200 ACB, retumbo 94.0 gr, F215M primer. No problems with cases after 3 firings. Decided to try Nosler brass hoping to improve accuracy. Case prep included full length sizing, trim to length, uniform primer pocket, and uniforming the necks with slight trimming. After first firing primer pockets had tremendous expansion. So much so 80% of cases would no longer hold a primer! Absolutely no other signs of high pressures. This was puzzling. Tried rem brass with same case weight and fired the rem cases again with this load. No problems. I've never seen this on any kind of brass in any caliber I've reloaded. I've fired hot loads with associated heavy bolt lift, sticky brass, flat primers, and very loose pockets. On these nosler pieces the new primer wouldn't hold at all. Can't believe you only get one firing out of such an expensive case. No special chamber or throat on my rifle. Nesika action, lilja 3 groove stainless barrel. Seat bullets to .020 off . 300 to 400 rounds so far. Has anyone seen this happen with nosler brass?

 

[Desert Fox]

Have you chronograph that load?. Why don't you chronograph both load and see what the difference in velocity. I had the feeling that you'll have higher velocity coming from the Nosler than the Remington.Nosler brass is probably soft and has less volume than the Remington. What you are seeing there is a sign of higher pressure, way above maximum. When you change component, always reduce your powder charge and work your way up again. You can't just change component and expect to get the same result. Brass varies dimensionally and from lot to lot.

 

[RMiller]

Did you work up to that load with the nosler brass?

If you change any component in your load you need to start low and work up again.