Like my nickel casings. Despite hearing they are more prone to crack. IDK. Found some cracks on one of mine.
It was my first/lead bullet in the mouth in my magazine; An after-market non-factory, not the same firearm manufacturer “mag”. Notice that in pistol mags, the very top opening has the pair of metal pincers which hold that first bullet in the mag. That part puts a lot of pressure pinching down on the very first bullet.
I think that’s what caused the cracking. My ammo happened to be of the higher cost and quality of a major manufacturer.
The crack was so fine/thin, it looked like a thread, hair, or like someone drew it with a lead pencil. I could feel it with my nail and finger.
Choose or replace after-market mags very carefully
Inspect your ammo early and often
Inspect your ammo when you clean your arms and mags
Invest in magnifying glass and bright lights (such as a folding lamp which has a large magnifying glass attached to it, not unlike a watch repairer’s or jeweler’s)
What harm or damage can occur from firing a bullet which casing is cracked?
Interesting my friend. I can see how as the magazine increases in number of bullets, the tension on the inner spring grows stronger, thus the very last round - the hardest to push in, thus the more prone to scratch against those pincers. The color of the marks matches the pincers on the mag. Think I’m not naming the parts correctly.
Those rounds were in my mag for a few months. Lots of tension. I got rid of the damaged bullet. All the rest were OK.
I think you are referring to the feed lips. But I strongly suspect the damage you were seeing was cosmetic though it is possible you had a defective case. I had nickel plated and regular brass cased ammo stored in fully loaded mags for over a decade as a test and they all fired without any issues.
Nickel plated cases are made from slightly thinner brass to compensate for the thickness of the nickel plate—the OD of the case has to be in spec in order to chamber reliably— that is why nickel plated cases have a reputation with those who handload for not surviving as many reloading cycles as unplated brass cases. Also, the hotter the load, the shorter the hull’s lifespan----this applies to unplated brass cases as well.
New factory fresh ammunition should definitely not have cracks, however if you’re shooting reloaded nickel plate ammo, well you get the idea. Cracked cases should be culled before reloading and shouldn’t pass inspection after.
SAAMI maximum operating pressure for 45 acp is around 21,000 psi. Other cartridges operate at even higher pressures. There’s really no way the feed lips of your aftermarket magazine could put enough pressure against a cartridge to crack the casing. Especially if you were able to load it by hand and it still functions in your firearm.
Good for you for being observant and rotating your carry ammunition though. I’d bet you a steak dinner that what you saw was cosmetic.
I’d probably disassemble the magazine and rub some scotch-brite against the sharp edges and see if it cures the marks.
I’ve wondered whether plated cases could “peel” if not done right. That would make a visible crack real, but superficial (i.e. not through the brass case). That could produce metal flakes in places you wouldn’t want them. Pure speculation — I’ve never seen it happen. I agree that feed lip pressure would not be the cause — if the case or the plating is cracked, it would be defective ammunition.
There’s plenty of brass in the world, so I don’t bother reloading the plated cases. The habit helps me with quick identification of duty vs practice ammo.
Knew someone who uses a CPAP machine for healthy sleeping and they used a pencil eraser to clean micro (invisible to the eye) debris off electrical connectors. Gonna try that; and I just got some cleanser from ShooterLube Company, I can try with the rough side of gun cleaner patches, on both magazines.