Ok,

Now that I have the overall length sorted out. I am at the last stage of my press. The book calls for a maximum of .473 diameter crimp. I am crimping to a diameter of .470. Will there be any added pressure that could be harmful if I crimp to that diameter? Thanks all.

Sid

That's a lot of crimp, especially if the bullets were of .452 dia. to start with. If jacketed, you must have REALLY made an impression on them! If cast, they stand a good chance of being undersized for the bore. Yes, you'll have higher pressures to release the tightly held bullet - how much and if harmful will depend on how high you've loaded the cartridges and what type of powder you're using.

The problem with the book diameter is that it assumes that all cases are the same thickness, and that is not so. When using a taper crimp die like that used for the .45 ACP, you should not put in more than .002 inch of crimp (.001 on each side). You are shooting a .451 bullet (jacketed, maybe .452 if lead). You case wall thickness could be .008 to .012 inch. That is a lot of difference and it could be more, I am just making up numbers to make a point. If the wall thickness is .010 inch, double that, add that to your bullet diameter of .451, and you have .471, so a .470 crimp is perfect for that and a .452 bullet. Now, if your case wall is .014 inch thick, .451 + .028=.479, and even a .473 crimp is WAY too much. Get my meaning? Measure the bullets, measure the case wall, add together and from that total, subtract .002 inch. That should be your crimp to diameter with the .45 ACP.

That's a lot of crimp, especially if the bullets were of .452 dia. to start with. If jacketed, you must have REALLY made an impression on them! If cast, they stand a good chance of being undersized for the bore. Yes, you'll have higher pressures to release the tightly held bullet - how much and if harmful will depend on how high you've loaded the cartridges and what type of powder you're using.

I am using 3.8 grains of Clays. Concerns? While at lunch I adjusted the die for a .372 crimp.

... Now, if your case wall is .014 inch thick, .451 + .028=.479, and even a .473 crimp is WAY too much. ... Measure the bullets, measure the case wall, add together and from that total, subtract .002 inch. That should be your crimp to diameter with the .45 ACP.

I wouldn't want to try shoot your .479 bullets in my pistol - the SAAMI chamber diameter spec is .474" No way you'll close the slide without a hammer!

The case mouth should be straight, with no crimp needed, and finished diameter should be .473.

I had a lot A-merc brass with thick case walls that loaded to a diameter over .475 about .150" behind the case mouth, even though they're .473 at the mouth. They won't chamber. I can see where they hung up while trying to feed 'cuz the brass is scratched in a ring around where the seated bullet's heel is.

You can buy a cartridge gage from www.midwayusa.com that will measure all the critical dimensions.

Get a factory crimp die (LEE) and sail on.
Pepe Ray

I'm using UMC brass and I have a .002 crimp; .471 down to .469.