What is the perforated line around revolver cases?

[Smaug]

Is it put there by the manufacturer so the case rips apart when it has been sized too many times? If that happens, it's going to be a pain to get it out of the sizing die...

Material savings?

You can see what I'm talking about in the front-right 45 Colt cartridge in this photo:

 

[fxvr5]

It's called a cannelure. It's common to all sorts of handgun ammo.

 

[fxvr5]

Is it put there by the manufacturer so the case rips apart when it has been sized too many times? If that happens, it's going to be a pain to get it out of the sizing die...

Material savings?

​

No need to go conspiracy theorist.

 

[mdi]

It is a cannelure. A groove rolled into the case body to stop bullet set back and for identification.https://en.wikipedia.org/wiki/Cannelure

 

[Smaug]

It is a cannelure. A groove rolled into the case body to stop bullet set back and for identification.https://en.wikipedia.org/wiki/Cannelure

Hmm, seems totally unnecessary on the case. Would it prevent certain bullets from being used, like 300 gr.?

 

[fxvr5]

Hmm, seems totally unnecessary on the case. Would it prevent certain bullets from being used, like 300 gr.?

No.

 

[25-20 WCF]

Hmm, seems totally unnecessary on the case…

Only to those ignorant of its function. The cannelure prevents the bullet from being driven deeper into the case, as in a tubular magazine. The first firing usually irons it out and all that is left is a shadow on the case. I’ve loaded thousands of .45 LC cartridges with those cannelures and have never seen a problem related to them. Don’t overthink this, just load and shoot.



.

 

[lightman]

I've loaded thousands of 38's and 357's that had cannelures with no problems. They mostly get ironed out on the first firing. Never had one separate there.

 

[Walkalong]

For the reloader, you can ignore it.

 

[Smaug]

No.

Very helpful. Thanks.

 

[Smaug]

Only to those ignorant of its function. The cannelure prevents the bullet from being driven deeper into the case, as in a tubular magazine. The first firing usually irons it out and all that is left is a shadow on the case. I’ve loaded thousands of .45 LC cartridges with those cannelures and have never seen a problem related to them. Don’t overthink this, just load and shoot.



.

Is it for the bullets that don't have a crimp cannelure, or just an extra measure of safety?

 

[fxvr5]

Is it for the bullets that don't have a crimp cannelure, . .

No.

. . . or just an extra measure of safety?

Yes.

 

[entropy]

In the era of lever carbines in calibers like .45 Colt, it was extra assurance that the bullet wouldn't be pushed down in the case farther, which would have caused dangerous over pressure. Modern levers don't need it, nor do revolvers really. Load 'em up and Choot 'em!

 

[mdi]

I believe it was intended as a "Just In Case" measure. Preventing loose crimps from allowing bullets to move deeper in the case, possibly causing dangerously high pressure. I can't remember any cannelures on semi-auto cases, but then again, I'm old...

 

[Varminterror]

“Material savings?” I can’t quite put my finger on how this could be? What way would you think the cannelure would promote material savings?

To your question about the case failing at the cannelures - albeit not designed as an intentional failure point - I can appreciate it might make sense that the cannelure would create a weak point in the case body. However, I have never seen evidence that this application of cannelures actually cause case separations at the cannelure line. I’ve seen photos online where TERRIBLY moisture corroded cartridges could be manually broken with ease, but I don’t recall ever seeing claims of a firing separation due to a case cannelure.

 

[EricBu]

It's so you know where to cut your ragged out 357 brass to make 38 SPL. J/K.......I've ignored them for years, and never even thought about it until OP asked the question. Now I know what it's for;-)

 

[Y-T71]

In the era of lever carbines in calibers like .45 Colt, it was extra assurance that the bullet wouldn't be pushed down in the case farther, which would have caused dangerous over pressure. Modern levers don't need it, nor do revolvers really. Load 'em up and Choot 'em!

What features do "modern levers" have that "older/antique levers" do not that makes them unnecessary?

 

[GeoDudeFlorida]

What features do "modern levers" have that "older/antique levers" do not that makes them unnecessary?

Automobiles.
Not nearly as many folks galloping hither and yon, yon and hither, across the fruited plains, with lever carbines bouncing around next to a horse’s withers in a scabbard.

Gravity, bouncing and vibration play heck with loose cartridge necks.

 

[DukeConnor]

In the era of lever carbines in calibers like .45 Colt, it was extra assurance that the bullet wouldn't be pushed down in the case farther, which would have caused dangerous over pressure. Modern levers don't need it, nor do revolvers really. Load 'em up and Choot 'em!

I'm pretty sure 45 colt didn't appear in levers until the 1970's

 

[Y-T71]

Automobiles.
Not nearly as many folks galloping hither and yon, yon and hither, across the fruited plains, with lever carbines bouncing around next to a horse’s withers in a scabbard.

Gravity, bouncing and vibration play heck with loose cartridge necks.

Sounds good to me!

Recoil has always been the reason I had in mind.

 

[Y-T71]

I'm pretty sure 45 colt didn't apoear in levers until the 1970's

1985 stands out in my mind for some reason.

I might be wrong but please don't tell my wife!

Either way it's probably reasonable to consider it modern.

On second thought, that still doesn't mean it's "modern"...

 

[GeoDudeFlorida]

In the Colt cartridge, it’s probably got more to do with packaging than use. The packaging for cartridges used to be stiff paper wrapped and folded around a stack of loaded cartridges. Put them in a pile and the bottom “box” is bound to get a little squished. With black powder cartridges that’s not such a big deal but with smokeless, that can be a problem. That cannelure won’t hold up against a lot of weight but it will bulge if the base is pushed past it. Gives a visual and tactile warning that something’s not quite right.

 

[Y-T71]

In the Colt cartridge, it’s probably got more to do with packaging than use. The packaging for cartridges used to be stiff paper wrapped and folded around a stack of loaded cartridges. Put them in a pile and the bottom “box” is bound to get a little squished. With black powder cartridges that’s not such a big deal but with smokeless, that can be a problem. That cannelure won’t hold up against a lot of weight but it will bulge if the base is pushed past it. Gives a visual and tactile warning that something’s not quite right.

After your reply about automobiles, I got to thinking outside the box a little more.

Do you think cartridges exposed in belt loops might have been a problem?

Chances of .45 colt ending up in a belt loop would've been pretty good I'd imagine.

 

[EricBu]

I don't think 45 Colt was in lever guns until the 1980s, so that's out. IIRC my old timey gun history, 45 caliber straightwall cartridges sucked in early years because the case head couldn't withstand extraction once the gun got hot, so they didn't really work well in repeaters. One of the reasons for the 44-40.

I've seen the perforation more on 38 SPL than anything else. The comments about preventing setback make sense to me...38 SPL was THE short barrel revolver round back in the day, and some of those snubbies had some serious recoil...I would think the rise of snubby revolvers probably increased the possibility and occurences of setback, so the mid case crimp makes sense to me there.

 

[fxvr5]

I've seen the perforation more on 38 SPL than anything else. The comments about preventing setback make sense to me...38 SPL was THE short barrel revolver round back in the day, and some of those snubbies had some serious recoil...I would think the rise of snubby revolvers probably increased the possibility and occurences of setback, so the mid case crimp makes sense to me there.

Recoil does not cause setback in a revolver's ammo. It causes bullet pull.