I never measure cases, but I do use a case gauge on every piece of sized 9MM brass and scrap those that fail the gauge. It must fall back out of its own weight. We had a poster in the past that said the longer cases shot better. Maybe an experiment is due?
Stop reloading 9MM cases at .744?
- Thread starter sbwaters
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CoalTrain49
Member
I'm a fairly new reloader so nothing I say should be considered worth much.
I've found that the absolute worst cartridge brass to manage is 30 carbine. It's like a 9mm on steroids, lots of pressure and head spaces just like a 9. There are lots of warnings about brass being too long creating a situation where the bolt won't close on the cartridge but can still fire. I've never heard of a problem with the brass being too short. I've actually used some that were .003 too short without issues.
I would expect the same would be true for 9mm.
I've found that the absolute worst cartridge brass to manage is 30 carbine. It's like a 9mm on steroids, lots of pressure and head spaces just like a 9. There are lots of warnings about brass being too long creating a situation where the bolt won't close on the cartridge but can still fire. I've never heard of a problem with the brass being too short. I've actually used some that were .003 too short without issues.
I would expect the same would be true for 9mm.
bluetopper
Member
Occasionally a 380 brass will get mixed in with my 9mm brass and get loaded as a 9. They shoot just fine too in a 9mm handgun. So no, being too short hurts nothing.
Ah, the case of "The Incredible Shrinking Brass". Sounds like a 1981 Lily Tomlin movie.
I don't measure each case, but I do pick a sample and check to make sure they're not stretching too much. I don't share your experience of having my 9mm grow shorter each time and I tend to lose cases to the weeds before most get five firings on them, so its not something I monitor too closely.
But since you know that you are experiencing brass shrinkage, you will need to set a standard measurement at which point you quit using your shrinking brass because it will eventually become so short that neck tension and proper hold on the bullet will become a problem. It seems to me your rationale for choosing 0.743 as that standard is well-reasoned and sound.
I understand. Turn that 30 carbine case into a 22 caliber bottlenecked case and those problems multiply.
The M1 Carbine was designed with a "shroud" machined into the bolt around the firing pin that prevents the hammer from striking the firing pin if the bolt is not fully closed. Also, there is a cut in the receiver bridge which will not allow the firing pin to move forward if the bolt is not fully closed. See http://www.m1carbinesinc.com/safety.html
If EITHER of these systems is functioning, the carbine cannot fire from an unlocked bolt.
The problem with the M1 Carbine is that the World War II vintage rifles are now 70+ years old and the 1950's, 60's and 70's vintage commercially made carbines may not have had these safety features properly machined or properly hardened so that they may be susceptible to failure even if present. The problem is real, but can be easily checked by field stripping the rifle and carefully inspecting the parts (or having a gunsmith inspect the parts if the questions are whether the parts were properly hardened).
Dudedog
Contributing Member
measure 9mm bass, no just clean,inspect for case neck splits loose prime pocket an those, then load shoot, repeat.- Status
