AR-15

AR-15
AR-15 Carbines

Sunday, June 19, 2011

17HMR Shooting and Split Cases

I spent some extended time at the range yesterday with the Savage 17HMR.  It was nice to have some extra time to chat with the other guys at the range, and to take my time working on aim and breathing. This was my best group of the day (50 yards 5 rounds, white circle is 1" across):

 I also noticed while picking up my brass, that I had quite a few split where the case necks-down.  Being a bolt action rifle I'm not worried about it, but if I had a semiauto it would be concerning. 8 rounds out of 50 had split, with this one being the worst.
I did some searching online about this issue, and this was the response one individual had received from Hornady (the ammo I use) "The 17 HMR cases may crack because of the annealing process when they are made. The annealing process is what makes the material brittle or flexible depending on the length of time and degree of the process. This is a precise procedure with any other case that can be reloaded, as we want the case to be hard enough to do the job but soft enough to stand up to several reloads. The 17 HMR case is dispensable and can not be reloaded, therefore the annealing procedure isn't quite as strict as with other cases. When the case cracks, it's because the neck was annealed a little harder than it needed to be, making it more brittle. This does not affect the accuracy or performance of the ammunition. Normally, the fired case will eject the same as any other, and unless they are picked up later, the shooter may never even know they had a case with a split neck. We would prefer that none of the cases split, (and the majority of them don't), but it seems redundant to spend the time and money on perfecting the case when it isn't practical or necessary. Our lab has evaluated cases with cracked necks, and the powder is fine, the case necks are just more brittle."

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