Because defensive ammunition is expensive I find myself seldom shooting it at the range. Due to this I end up cycling my carry ammunition through my gun with notable frequency. When you cycle the same round through a gun with any frequency you can cause a problem called bullet setback; this is when the bullet gets pushed back into the casing by slamming against the feed ramp numerous times. After a while the bullet can get setback in the case enough to cause a dangerous buildup of pressure when you finally fire the cartridge.
Knowing this I periodically take a micrometer and compare the overall length of the cartridges in my carry gun with factory ammunition of the same time that hasn’t been chambered. If the cartridges in my carry gun start becoming shorter then it’s time to switch out ammunition. Since I did my ritual of ammunition check and cleaning last night I though I’d post a reminder that those of you carrying pistols should do the same once in a while.
I would also like to present a tip for alleviating bullet setback. Instead of chambering the same two rounds all the time (the top two in the magazine) place the previously chambered round at the bottom of the magazine. This takes a bit of time but it ensures all of your ammunition has been chambered roughly the same number of times and reduces the number of times each bullet has been chambered.
One thought on “Checking for Bullet Setback”
If you are going to be at the range and you want to take your carry ammo out, you could always just shoot the chambered round without the mag in there and switch to your range ammo after that point. I am actually getting to the point where I want to run at least one mag of carry ammo through my gun every 3 months though just to keep things fresh. It isn’t that expensive ($0.50-$1.00 a round vs $.20 a round). It is a great way to make sure your gun is happy with your carry ammo, and gives you an opportunity to switch carry magazines at that time to so you rotate things.
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