I usually use Varget in my 22-250, but recently loaded up a batch with IMR 4895. (Identical velocities.) A lot of the necks started splitting. Any ideas what caused this? Does 4895 burn hotter or something?

I have just started reloading so I am no pro, But I found this web page that has almost all the burn rates for many different powders. 4895 is 99 on the list and Varget is 105 with 1 being the fastest and 153 being the slowest. Also there is no hodgdon powders between them. Here is the link and hope it helps. http://www.204ruger.com/burn_rates.php

I have yet in my life seen a powder that causes neck splitting. That is usually caused by working the brass. And usually can happen after 3-5 reloadings. A higher pressure load could increase splitting.

You can soften the brass by annealing it. I suspect the brass has gotten brittle with age

All brass has been shot the same number of times, but only the cases shot with the 4895 have been splitting. The only variable appears to be powder, which is why I posted the question.

I have no idea whether faster powder is also hotter powder, but perhaps someone out there can comment. FWIW to achieve equal velocities (3700 fps with 55 grain slugs), I used 35 grains of the faster 4895 and 37 grains of Varget.

Here is a pic of brass that split I believe because it is brittle with age.
This is a factory load Remington kleenbore express



Not on the neck but split. Glad I wear safety glasses

the 4895 is not the culprit....look elsewhere.

Agreed, the powder is not going to cause the case necks to split, age and working the brass is the culprit. You MAY increase case life by just neck sizing but it's been my experience that it won't be that noticable.

Exactly! Your powder choice has noting to do with neck splitting. Anneal your cases!!

Agreed on it not being your choice of powder causing neck splitting. I've been loading for 40 years and have never heard of that one before. Annealing will solve your problems.Each time you fire and resize your brass, it becomes more brittle. The annealing process will bring it back to it's soft old self and stop the cracks.