"Cannelures" on cases

[flabbydan]

Why is there a cannelure (sort of) on the brass of some of the less-expensive brands of handgun ammo, such as Sellier & Bellot, Federal American Eagle, etc.?  I've noticed it especially on revolver cartridges.  I use the word "cannelure" loosely here, as I'm not sure that's what you'd call it.  I mean on the outside of the brass--not the one on the bullet.  I've always wondered about this.

Dan

[LaOtto222]

I do not know either. I have seen it on 44 mag and 357 cases of Remington manufacture too. I thought so and just checked, and they were there, but not in all of them. I would guess it has some thing to do with the factory loading process. Maybe they put it in there to prevent the bullet from going too far down in the case before it crimped, or it is a way of grabbing the case during a step in the loading process I have not noticed it on new cases, that have not been loaded from the factory, but that does not mean they are never there. Maybe some one that works at a ammo factory will fill us in.

[quickdtoo]

You'll notice in the pic below, the "dimples" are at the base of the bullet on the 45-70 405gr Remington loads, it performs the same function as a crimp in a cannelure, the 405gr Rems are too long to crimp in the cannelures and feed thru a levergun, so they do the dimples, I guess.

Tim

[John Traveler]

Case cannelures are routinely used to prevent feeding/recoil impacts from driving a bullet deeper into the cartridge.  They provide additional bullet positional security with the usual mouth crimp and were also used to visually identify the load; i.e. different bullet weights for identical-looking cartridges.  Examples include the Remington and Winchester .38 Special ammunition in standard velocity 158 and 200 grain loadings, also the 158 high speed "police" loadings.  These various loads use one or two case cannelures in different positions for load identification.

[flabbydan]

Thanks for the info!