Ring around the bullet

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SoylentD

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Hey all.

Im new to reloading and want to get your opinions on reloading pistol - 9mm and 45acp.

My dies are not taper, or at least I dont believe they are. The seating and crimp (lack of a better word) is good and solid. The bullet itself doesnt move or anything. But when I dissasembled the projectile, there is a slight ring where the end of the brass dug in a bit.

I generally assuming this isnt good for ballistics. I took apart some local reloads, and they have the same ring. I took apart some factory and it isnt there. Some wolf reloads had very minor rings too.

How worried should I be about a ring around the bullet? I shoot ipsc and looking to increase accuracy, not mess it up with random flyers.
 
Sounds like you have a strong crimp. Does not need to be strong except with heavy bullets in a revolver.

Back your seating die out a quarter turn, if you want less crimp. But after that bullet gets kicked in the ass with 20,000+ psi, the ring won't exist.
 
Taper crimp die will have 'TC' stamped on 'em. It's only the seating die(A TC die can be setup to seat and crimp in one step) or can be a separate die though. They'll will squeeze the lead a bit, but it's nothing to worry about.
 
When you taper crimp any semi-auto cartridge it is not a true crimp and it is more streamlining the case mouth for proper chambering. A roll crimp on a revolver case will "bite" into the bullet to help build up pressure with slower burning powders.

Below are some exaggerated examples of crimps, and "normally" a taper crimp is only .001 to .002 smaller than the actual case diameter around the bullet. This is very important when shooting plated bullets because if the copper plating is penetrated by the crimp leading and accuracy will suffer.

Crimps-3_zps15b1fd66.jpg


Below has to do with the burning rate of the powder and your crimp, this is a very mild .44 Magnum practice load with a fast burning powder that is 100% burnt in just a little over 4 inches of barrel length. On this load I use a slight taper crimp and not a roll crimp for two reasons, 1. It is not a magnum load and the bullet will not move under recoil 2. The fast burning doesn't need a tight crimp because and is totally burned before the bullet leaves the barrel.

44231_zps745df461.jpg


Bottom line, you do NOT need to over crimp all your hand gun rounds, and your semi-auto cases like the 9mm and 45 auto only need a "slight" crimp to streamline the mouth of the case. Keeping in mind the case is to have a tight grip on the bullet and is actually what holds the bullet in place and not the crimp.

"Generally" you have enough crimp if you put hand pressure on the loaded round and the bullet does not move back into the case. And this will depend on your dies, case wall thickness and the size of your bullets. (nothing is written in stone)

And the vast majority of reloading manuals will explain this in the front part of the manual that so many people forget to read.
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Just be cautious not to over crimp un-rimmed straight wall cases such as 9mm and 45 Auto as these cases headpsace on the case mouth. Under ingition push from the firing pin, too much crimping may cause the case to go too far past the chamber resulting in extra headspace and can also create a high pressure if the case mouth is partially engaged too far in the barrel. For that reason case lenght must also be kept under spec.
 
Just do what the reloading manuals all tell you to do, and go get a taper crimp die. Don't cost much, gives the correct end product, and eliminates the possibility of a roll crimp allowing the case to move forward, and then exhibit vastly excess pressures as the bullet tries to force its way past the end of the chamber, filled with brass! And, if your case is too long, and you use a roll crimp established with trimmed cases, you may just cut the jacket sufficiently to have it separate in the barrel. Generally poor practice.

I guess my bigger question is, why bother if you ain't gonna do it right?
 
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