Probably a dumb question but I'm still curious. In a loaded 458 cartridge, how much taper is there, typically, from the case mouth to the base of the bullet(I realize that bullets have different lengths.) I saw that the SAAMI max cartridge dimensions show a continuous taper from the case mouth to the belt(.014" per inch). Does that work well for bullet tension? Is wall thickness of the brass thinner for a certain distance from the case mouth then gradually gets thicker, or does it just gradually get thicker from the case mouth to the base? I appreciate your help.

The SAAMI drawing does not take into consideration that your sizing die makes the brass smaller than the bullet and then, you insert the neck expander in there, it makes the inside parallel. Case walls do get thicker the farther back you go, but in the area of bullet tension (neck), it is slight, and the taper, slight as well, so your neck tension is fairly uniform. I sense that you have a lot of time on your hands to think about this since it has worked for a long time. All straight walled cases have this phenomenon to some extent.

quote:

Originally posted by dpcd:
I sense that you have a lot of time on your hands to think about this since it has worked for a long time.

Not sure exactly what you are implying by that, but I appreciate your response. I've never had the pleasure of holding 458 Win cartridge in my hands, so all I had to go by was the SAAMI specs. I had it in my head that the bullet tension relied heavily on the crimp. By looking at the drawing it appeared only the first bit if the case mouth would have good tension on the bullet, then the case would taper out leaving less and less tension towards the base of the bullet. Obviously, I thought wrong. It's in my nature to want to know how things work, that's all. Plus I have my 458 Win Mag on the way, so I have to learn to reload for the darn thing. I've only reloaded bottle neck cartridges and pistol cartridges. Never a "straight walled" rifle cartridge. It seems to be a lot like reloading for a handgun cartridge.

+Templar+ crimp with a LEE factory crimp die. Better than roll crimp. I have had problems with roll crimp actually loosening grip on the bullet.

Yes the case will hold the bullet with good tension, for bolt action I use the lee die.

Good luck and good shooting.

Cheers, Chris

I'm too lazy to cut open a 458 case to see how the wall thickness varies. Since I sold my 458 I might not even have one any longer. I do know my old Hornady dies would size the case far enough that the bullet would actually have to expand the case as it was seated. It would hold the bullet without a crimp. Didn't have a lee crimp die so I had to work with die to get it to crimp correctly.

I only meant that it seemed that you, like me, spend a lot of time contemplating on how things work; and the first thing we do on getting anything new, is take it apart. Even if it works correctly.
You are right, loading straight walled cases is like loading pistol ammo. No need to worry about the case taper affecting the bullet pull; your dies will work there. One thing TO be concerned about with the 458 is that some loads want to be highly compressed as the 458 is not a huge case. I didn't like compressing loads too much as they can cause the bullet to be pushed out; hence the need for a good crimp. This is why they invented the .458 Lott. Personally, I found the 458 to hold enough powder; but I no longer own one.