If you’re like me, the rimfire ammunition shortage has seen you go deep in your stockpile. In my case, some of the .22 LR stuff I’ve been shooting lately looks ratty, although I have yet to encounter any function problems. I take the usual precautions, but this week I ran into something rarely mentioned when testing an Alexander Arms AAR-17-chambered in .17 HMR.
When I policed up nearly 300 pieces of brass, I discovered three cracked case necks so I called the rifle’s designer, Bill Alexander. He is undoubtedly one of the nicest people in the industry and he always eagerly shares his wealth of knowledge.
Part of his design challenge was that the early ammunition was, well, “sporty in a self-loader” is a polite way of putting it. Usually a factory anneals (heats and cools) a cartridge’s case at the bullet end to make it more pliable. The treatment reduces the chances it will crack as the company inserts the bullet, or spring a leak at the shoulder or neck when you touch one off at the range. Norma has a good explanation here.
However, the .17 HMR is really a .22 WMR necked down to .17 caliber. The original rimfire .22 magnum has a straight case (ignoring that rim), so quality ammo is annealed, primed, powder goes in and the bullet is inserted. The .17’s slender neck made it impossible to get primer at the rim after necking, so the primer went in first. Then it was necked down, which precluded annealing because the heat required would set off that primer.
As a result, case-neck cracking was common. Things have changed since the cartridge’s introduction in 2002, though, and Alexander said one of his biggest design challenges was making sure his rifle could handle the older fodder. It did with aplomb in my case, with only three cracks, all from the same lot and manufacturer (from what I can gather produced in 2005). There were no failures to fire, squibs, odd velocities or damaged cases from fresher cartridges provided by other companies. Alexander said he’s seen fewer problems with new ammo (although cracking still occurs), and even had to resort to making faulty cartridges to test his rifle’s ability to protect shooters during a catastrophic failure.
I’m still waiting for confirmation from manufacturers that they’ve altered the process, but in the meantime, I’m rethinking the 10-year-old .17 HMR in my ammo bunker. It’s my understanding those cracks I detected after my range session were probably there before I began to shoot-microscopic little fissures, letting moisture in by the second, increasing the chances the powder will fail just when the zombies attack.
Don’t get me wrong. I won’t be getting rid of my guns in the chambering. The rimfire’s performance is too good for that to be an option. However, there is a good lesson to be learned: Not all cartridges/loads are created equal in regard to long-term storage.