No one has posted anything factual yet?
My experience with 44-40 bullets telescoping back into the case in a rifle with a tubular magazine is not factual?
My photos of cannelures on old 38-40 ammunition is not factual?
Here are a couple of more non-factual photos.
The ring is to prevent the bullet from being pushed into the case
I think the cannelures aid in manufacturing. They keep the bullet from going too far into the case on the automated presses. This is my theory. I do not know if this is for sure.
Wrong.
This is a photo of a round of modern manufactured Federal American Eagle 38 Special, 158 grain Lead Round Nosed ammo. Actually it is a photo of two rounds. I pulled the bullet from one round and placed it alongside the bullet with the empty shell. Notice the position of the cannelure. Notice how much space there is between the bottom of the bullet and the cannelure. A quick measurement shows there is approximately .100 or so between the bottom of the bullet and the cannelure. So much for cannelures preventing a bullet from being seated too deep in a cartridge. The cannelure is nowhere near the base of the bullet. Peeking down inside that 38 Sp. case, that cannelure barely makes any impression on the inside of the case at all, it most certainly would not prevent a bullet from being shoved past it by any sort of bullet seating equipment.
Another non-factual photo. Various cannelures on old ammunition. The first two rounds were in an earlier photo I posted on this thread. A 38-40 round made by the United States Cartridge Company and another 38-40 made by Remington-UMC. Next is a 44-40 round made by Winchester Repeating Arms Company. (By the way, yes the headstamp is 44-40, not 44WCF for those who think Winchester never used that name.) Next is a 45 Colt made by Winchester Repeating Arms, and finally an unusual 45 Colt made by Frankford Arsenal. This is one of the rounds with an extra wide rim for the 45 caliber Colt double action revolvers.
No, I am not going to pull any of these bullets, they are part of my cartridge collection. Are these cannelures deep enough to prevent a bullet from telescoping back into the case? Hard to know without pulling the bullets and measuring where the base of the bullets sit compared to the cannelures. I suspect that really deep cannelure on the 38-40 all the way on the left may be just for that purpose. It is really deep. The two 45s on the right? Those cannelures are not very deep. I suspect even if they are positioned at the bottom of the bullets, they are not deep enough to prevent a bullet from being pushed past them.
The leverage available on modern reloading presses or commercial loading equipment provides a great deal of force when seating a bullet. No matter how deep the cannelure is in a soft brass cartridge case, I submit that it would be useless in preventing a bullet from being shoved past it. I don't know about anybody else, but when I reload my ammunition, I set my dies very carefully. The setting of the dies is what governs how deep the bullet seats, nothing else. Certainly not a cannelure in the case.
I suspect the great majority of cannelures on modern ammunition are just there, as my good friend Bob Wright says, merely for quick identification of the ammunition. I don't buy a whole lot of commercial ammo these days, I had to scrounge around on my shelves to find some ammo with the modern 'really light' cannelures such as on that Federal 38 Special ammo. But I submit these shallow cannelures on modern ammo have nothing to do with preventing bullets from being seated too deep.
P.S. and they have nothing to do with how much Black Powder to dump into a cartridge. Oops, I have only been loading Black Powder in cartridges for 20 years, I guess that is another non-fact and I don't know what I'm talking about.