What do the bands on 38 Special cases mean?


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Minnesota Wild
June 14, 2011, 12:04 AM
So I've been trying to find an answer to this question without success...several brands of 38 Special cases I load have bands printed into the brass, while others are just plain smooth cases like all my auto brass. It seems that there is either a single band about 1/4" under the case mouth or two bands a little farther down, and I've seen this with several brands of cases.

So what's the purpose of the bands? Does it indicate something about the brass, or is it for some purpose?

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ColtPythonElite
June 14, 2011, 12:06 AM
No purpose.

gamestalker
June 14, 2011, 12:09 AM
Those are case canelures. Some auto loading brass has them also. They have a primary purpose of preventing bullets from inadvertantly seating deeper. I believe the ones with double canelures may be one for a lead bullet and one that would apply to a jacketed bullet?

bigedp51
June 14, 2011, 01:12 AM
We have a Bingo

http://i122.photobucket.com/albums/o254/bigedp51/crimp.jpg

In another forum a person with a 1911 .45 was having problems with bullet setback on his duty carry weapon.

The answer was the type cartridges above and STOP unloading and loading his pistol every day before he had serious problems in a firefight.

ArchAngelCD
June 14, 2011, 01:44 AM
They usually "iron out" after a few loadings and will not interfere with reloading.

ColtPythonElite
June 14, 2011, 10:39 AM
I don't believe those rings he is talking about are cannelures on .38 brass. I have lots of old brass. Some of them have two rings. One is only about 1/4 way from the head of the case. There's no way you'd ever be seating bullets that deep.....They do not iron out after loading/shooting. They are more of a decorative nature as a way to mark the brass, I believe. Almost like the numbers on a golf ball.

ReloaderFred
June 14, 2011, 11:00 AM
Any "ring" around a cartridge case is called a cannelure. It can have several different purposes. The original purpose was to prevent a bullet from seating further into the case (bullet setback) in autoloading pistols and revolvers. A second cannelure higher up was to help with bullets pulling out under recoil in revolvers. These days it's also used to identify different brands and types of ammunition.

In the late 1800's and early 1900's, ammunition could be handled roughly and carried in saddlebags for an extended period of time. The bullets were pretty much pure lead and soft, with a BHN of around 5 or 6. Neck tension and crimp weren't always successful in holding the bullet in place, so cannelures were added.

I've seen cannelures within 1/8" of the case mouth on S&B .38 Special, and within 1/8" of the case rim on MagTech .38 Special. I've also seen cannelures used on military 5.56 cases near the base of the case to indicate blank ammunition, etc.

A cannelure can have many uses, both practical and cosmetic.

Hope this helps.

Fred

Friendly, Don't Fire!
June 14, 2011, 11:04 AM
There is actually a tool you can purchase that will put a cannelure on your brass if you want it!

http://www.corbins.com/hct-1.htm

http://www.corbins.com/images/hct-1.gif
http://www.corbins.com/images/hct-1.gif
http://www.corbins.com/images/hct-1.gif

ReloaderFred
June 14, 2011, 11:07 AM
I use the C-H Cannelure Tool, but mainly for adding cannelure to bullets. It's about half the price of the Corbin tool.

Hope this helps.

Fred

gamestalker
June 14, 2011, 12:52 PM
They are not a decorative feature, that's for certain. They're primary purpose is to prevent set back or forward jump. I saw some additional information with older brass that explains the ones that are real close to the head. Those are to hold a paper disk over the top of light loads of fast burning powder to produce a more consistent ignition than if the powder were to just lie on the wall of the case. Since I don't load with light charges of any type powder, I'm not familar with the terminology for this disk, maybe it's called a gas check? Anyone? I think I read about this in my Speer manual.

rcmodel
June 14, 2011, 12:58 PM
How about over-powder wad?

And I agree no manufacture puts cannelures on cases just for decoration.

They would be foolish to invest the extra manufacturing step and cost involved unless there was a legitimate ballistic or safety reason for doing it.

rc

goon
June 14, 2011, 03:52 PM
I've seen the cannelures in strange places on my .38 Special brass too. It doesn't interfere with anything so I just load it and don't worry, but I also wonder what they were thinking sticking cannelures so far back toward the head of the case.
At least until I get the loaded round in my chamber. At that point, I forget all about the cannelure and release lead at targets.

helotaxi
June 14, 2011, 09:54 PM
There is a reason: to mark different loads that otherwise look identical. The same thing is sometimes done to the bullet; a cosmetic cannelure in front of the crimp cannelure so the user can tell the difference between 125gn, 140gn and 158gn loads at a glance.

RidgwayCO
June 15, 2011, 11:27 AM
Here's a photo of CH4D's cannelure tool:

http://img11.imageshack.us/img11/9739/ch4dcanneluretool.jpg

Wil Terry
June 15, 2011, 11:34 AM
CASE CANNALURES are used for many things by ammunition manufacturers. The use as a stop for the bullet is noted but mostly they are used to identify a load when there is a load in the lineup that looks the same. It is also used to identify the brass as having been made for a specific load, or as having been loaded by the ammunition plant and it not part of brass sales to handloaders, among other things.
And so it goes...

Minnesota Wild
June 16, 2011, 12:24 AM
Thanks for the responses! I've been reloading for a few years, and I never knew what these were for. It looks like they are cannalures. That makes sense for the ones that are just below the case mouth, but the fact that some have two of them made me wonder. I guess for those they must just be for telling the difference in the ammo? I thought they may tell you something about the load...

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