Crimp for cast bullets

[45 2.1]

Bob,

I am embarrassed and willing to show my ignorance for the purposes of education.

I can only think of two functions for a crimp.

1. To hold the bullet in place.
2. To seal the contents from the elements.

Are there more that I am missing? All of the reasons I can possibly think of are traced to these two.

Bass-
Normally, people think the crimp is to keep the bullet in place, either from pulling or pushing into the case. Crimp is also used to control the burning characteristics of the powder in use or to retard the release of the bullet. It really depends on just what the objective is. This can be a very comprehensive subject just as use of fillers is. Do you remember the fight between LEE and I think Speer when LEE brought out there factory crimp die. It was claimed that the factory crimped helped the powder to burn correctly, which was a very true but very new statement to most reloaders. The degree of crimp changes the function of how a powder burns. Powders, depending on how fast they burn, usually need some restraint to reach a certain pressure to burn correctly. The slower they burn, the more restaint they need. Either from heavier bullets, filler use or crimp. It can also effect just how good of accuracy you can obtain.

[Bass Ackward]

Actually, BA,

I can only think of ONE function for a crimp.

1. To hold the bullet in place.


felix

Felix,

Well OK. I was thinking of the military as they crimp necks and primer pockets to seal out moisture. But as far as cast goes, I would say one.

Hey Felix. Joe has some bubblegum that would make a good sealant. He was trying to con me into using it for lube but I fooled him boy. Couldn't get it to blow bubbles worth a darn. And it had a slight petroleum odor, but it lasts a long time.

[imashooter2]

Felix,

Well OK. I was thinking of the military as they crimp necks and primer pockets to seal out moisture. But as far as cast goes, I would say one.

-snip-

The military crimps the case mouth and primer pockets to ensure a pushed back bullet or blown out primer doesn't tie up the gun. They waterproof the case and primers with lacquer and/or tar type sealants.

[StarMetal]

Yeah, I said Bass some bullet lube I made and he thought it was bubblegum. I said "God no, don't chew that stuff".

Joe

[felix]

Yes indeed, I also use crimp power to hold a boolit back a little more for better ignition when using the slower powders. A better and more consistant way is to use a smaller expander plug and use a light crimp only. But that assumes you don't resize cases until needed that day for a load in mind. Unfortunately, these days I just go ahead and size cases when there is nothing else to do with no load in mind. In this situation, I tend to expand the cases more to avoid squishing the boolits too much. Always best to load from scratch with a boolit and load in mind up front. ... felix