I have some old Winchester 45 Colt cases which have a small thin cannelure about 0.84' up from the head of the case. RP and Starline do not have them. Why are they there? These cases are old and this cannelure seems to be a failure point on the case. The case eventually cracks at this point.
Cannelure on case-why
- Thread starter olduser
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Do you have or have you seen any of those cases that cracked at that point??
also, are they balloon head, or solid head cases??
Take a light and take a good look inside the case. Use a tool and drag it up the inside of the case, looking for /feeling for a ring inside the case. If the cannelure does not bulge the interior case wall, then its an ID marking and highly unlikely to be a failure point.
A case cannelure that actually creates an indent in the case is usually to serve as a stop for the bullet base. I have brass like that, specifically some old .45ACP brass. The case cannelure prevents bullet setback.
I also have a bit of brass that has two cannelure rings (.38SPL) in the middle of the case. These are knurled rings that do not intrude into the case interior and I'm told were simply put there as an ID on the cases indicating that they were, or had been loaded with target ammo.
If you have a chance, look at some GI .223 BLANKS. They have a cannelure just above the head of the case. Its a marking who's function is to ID the case as being made as a blank. SO, even if someone trims off the brass crimp portion, its still evident the case was made to be a blank.
A cannelure on the case wall is not on a portion of the case that gets "worked" as much as the case mouth. Expansion on firing, compression during resizing. That's it. Even if it is a thinner spot on the case wall, its not worked any more than the rest of the case and it almost never fails at that point.
Also consider that 50+ years ago all the way back to early metallic cases, the reloading "service life" of a case was not the makers highest priority.
The old M852 brass has a cannelure way down near the head. You can see it in the image at the top of this page if you hover your cursor over it. It was military match ammunition made using the Sierra 168-grain MatchKing. At the time, the match bullet hollow points were not allowed to be issued for combat, so the cannelure was a quick way to look at a loaded round or an ejected case and see it was not approved for combat. Later, the Adjutant General's office declared the tiny hollow points in match bullets to be non-expanding hollow points and, therefore, not a violation of the Hague Accords to use in combat, opening the door for the development of the 175-grain MatchKing used in M316 mod.0 military sniper ammunition. But that didn't come until after M852 was still being made for the military match teams' accurized M14s. So, it is, as 44 AMP said, an identifier in modern loaded ammunition.
I've seen handgun cartridge cases that split at their cannelures and others in which the marks just ironed out over time and never caused a problem before the mouths started splitting (work hardening from repeated crimping). So I think the cracks are mainly just the particular manufacturing run having the cannelures a bit too deep. Other factors that may be involved are the exposure of the brass to any kind of ammonia traces in the air, such as from a Kitty Litter box or being polished with Brasso, which will eventually promote season cracking. Another is just the work hardening from shooting and resizing. In that instance, it is possible to anneal the cases in the stressed area, but handgun brass heads are so close to the annealing location that you have to use some kind of head chill to do it safely. Setting the heads in shallow water in a pan and then applying heat from a torch is a common way to keep them from overheating (dangerous, as heads can get too soft to hold pressure), but it will take some practice and probably isn't worth the bother if you have other brass.
I've seen handgun cartridge cases that split at their cannelures and others in which the marks just ironed out over time and never caused a problem before the mouths started splitting (work hardening from repeated crimping). So I think the cracks are mainly just the particular manufacturing run having the cannelures a bit too deep. Other factors that may be involved are the exposure of the brass to any kind of ammonia traces in the air, such as from a Kitty Litter box or being polished with Brasso, which will eventually promote season cracking. Another is just the work hardening from shooting and resizing. In that instance, it is possible to anneal the cases in the stressed area, but handgun brass heads are so close to the annealing location that you have to use some kind of head chill to do it safely. Setting the heads in shallow water in a pan and then applying heat from a torch is a common way to keep them from overheating (dangerous, as heads can get too soft to hold pressure), but it will take some practice and probably isn't worth the bother if you have other brass.
Brasso is great stuff, for the brass on your uniform, or other decorative items.
BAD STUFF for the brass in your gun! Uncle Nick is entirely correct about that. Doesn't cause instant failure, but weakens the brass over time.
Think of it as slow poison for cartridge brass.
Or, like "old movie disease" where the heroine is dying of something, lying in bed, getting more and more beautiful as they get weaker and eventually die.
BAD STUFF for the brass in your gun! Uncle Nick is entirely correct about that. Doesn't cause instant failure, but weakens the brass over time.
Think of it as slow poison for cartridge brass.
Or, like "old movie disease" where the heroine is dying of something, lying in bed, getting more and more beautiful as they get weaker and eventually die.
(Heh, I'm going to post after Unclenick and 44 AMP. Talk about a tough act to follow! 
)
I've always speculated this:
I don't load 45 Colt. But I do load a lot of 38, 357, 44 Special, and Mag. I have large quantities (many thousands) of cannelured brass in these calibers. In 39 years of loading, I have never had a single example of failure at these points. Lots of work-hardened mouth splits - as Unclenick describes - but nothing at the cannelures.
)I've always speculated this:
Never read it anywhere. Just a gut feeling; and I still believe I'm right. You won't see these marks on modern brass (at least, I haven't). And I have also speculated that's because ammo has become so expensive, the manufacturers take every measure to keep production costs down - and that includes nixing the "identification marks."
I don't load 45 Colt. But I do load a lot of 38, 357, 44 Special, and Mag. I have large quantities (many thousands) of cannelured brass in these calibers. In 39 years of loading, I have never had a single example of failure at these points. Lots of work-hardened mouth splits - as Unclenick describes - but nothing at the cannelures.
Can't think where I saw the post, but someone on one of the boards reported speaking with a manufacturer about it and getting the ID purpose information. I haven't done it myself, though I probably should. I did buy five boxes of Federal HST 230-grain 45 Auto ammunition through the Expert Voice marketing program in August of 2019, and it has a cannelure right about where the bullet base is. But it is just a marking cannelure and is not pushed into the brass to prevent setback.