45acp Crimp ?

[kidcoltoutlaw]

for the crimp how much is enough and is it the same for plated , lead and jhp's ?for the col how much im thinking if it will run in the mag and gun then it's ok as long as it's not to short.short can drive the pressure up,thanks,keith

[Run n Gun]

If you do a search you'll find a lot of recent information on how to properly calculate pistol cartridge crimp, including 45 acp. That said, I crimp lead and jacketed .468-.469 and plated .470-.471. Excessive crimping plated bullets will destroy accuracy. Rule of thumb; use as light a crimp as you can and still avoid bullet setback.

Ed

[blkbrd]

Don't think of it as a crimp, think of it as putting the case back into shape after belling, use just enough to ensure reliable feeding. You can destroy accuracy on just about any bullet using excessive crimp but plated seem even more picky.

Case tension should hold bullet from setback even if it is not crimped, if it does'nt ether your resize die is not small enough or your expander and powder die is to big.

I have found on Dillon powder dies that the expander is many times to big and needs to be polished down.

When you have good case tension you will get more consistant powder burn, softer shooting loads and better standard deviations out of your loads.

I have seen SD's go from 12-14 down to 6-7 just by increasing bullet case tension via EGW U die and polishing the Powder die.

[Gun Geek]

I have seen the same results (lower SD, cleaner burn, reliable feeding) from Lee Factory Crip Dies.

They work, they're simple , and they're cheap.

I know it is a religious war to discuss them. The argument I've heard against them is that if you do the other steps properly, FCDs are not needed. This feels a bit like "the only way to handload accurate, safe ammunition is to use a single stage press". An assertion I know as a fact is untrue.

[ghostrider]

Guys:

I'm new to the forum, but I have reloaded for many years. I try to tailor a crimp for a 1911 to fit the chamber of the gun. Take the barrel out, and try your bullet in the chamber. It should be perfectly even with the barrel extension. If it protrudes, crimp a little more. Most dies like the Lee are designed to make it difficult to over crimp.

[TBF]

If you do a search you'll find a lot of recent information on how to properly calculate pistol cartridge crimp, including 45 acp. That said, I crimp lead and jacketed .468-.469 and plated .470-.471. Excessive crimping plated bullets will destroy accuracy. Rule of thumb; use as light a crimp as you can and still avoid bullet setback.

Ed

To that info I can add :

Don't even think of it as a " crimp ", just as returning the mouth of the case to the proper dimension for feeding. Just remove the bell you put in to allow the bullet to enter the case.

Bullet dia. + 2X case wall thickness - .001 - .002.

.451 + .020 - .001 = ..470

.451 + .020 - .002 = .469

Travis F.

[short_round]

One rule that I have heard is to, while standing, put your thumb on the base of the cartridge then place the tip of the cartridge against the side of the bench and lean into it with your body pushing the bullet into the brass against the bench. If the bullet does not set back then you have enough crimp. I guess this would vary between someone who weighs 300lbs vs. 90lbs, but again it's just a general rule. The "crimp" is there to make sure the bullet does not set back. This will usually happen when the bullets slams into the feed ramp during cycling.

I have also pulled bullets after crimping to make sure that they are not "mushroomed." Although I know people who don't care if their bullets are indented like that.

I try to balance the two.

[tightloop]

In .45 with lead bullets, crimp to .469 or .470 if the bullet is .452.

Crimp to .469 or .468 with jacketed bullets which run .451

[silvervette]

Here are some excellent pictures of what a good crimp should look like

[silvervette]

One rule that I have heard is to, while standing, put your thumb on the base of the cartridge then place the tip of the cartridge against the side of the bench and lean into it with your body pushing the bullet into the brass against the bench.  If the bullet does not set back then you have enough crimp.  I guess this would vary between someone who weighs 300lbs vs. 90lbs, but again it's just a general rule.  The "crimp" is there to make sure the bullet does not set back.  This will usually happen when the bullets slams into the feed ramp during cycling. 

I have also pulled bullets after crimping to make sure that they are not "mushroomed."  Although I know people who don't care if their bullets are indented like that.

I try to balance the two.

Crimping has little if anything to do with preventing setback. go back ad read what

blkbrd said in his post

Quote"Case tension should hold bullet from setback even if it is not crimped, if it does'nt ether your resize die is not small enough or your expander and powder die is to big."

I stop measuring the crimp, I found that I can just eyeball the crimp to do a check

go back to the other post I made it has a link to another forum that has pictures of what a crimp should look like. As long as your finished cartridge looks like the pictures you are OK. You don't really think that little tiny edge on the crimp will hold the bullet in place do you? Try pushing on the bullet while it is still belled you will find no diffrence in setback before the crimp

[silvervette]

These are not my words but I am posting them here because he said it a lot better than I ever could on the 1911 forum

Here is what 50cal said on the 1911 forum and here is the link ito the thread if you want to read the whole thread

I would not lose too much sleep over crimped diameter. We do not want to fuse the casing to the bullet, the crimp IMO, just keeps the bullet steady so it doesn't move around while the gun recoils, and provides a smoother profile. If you have to crimp hard because the bullet moves in the casing you have other problems (bullet to small, over-expanded, brass to brittle...). Have you ever noticed that you can vary the reading of your caliper simply by using more or less pressure when you take your measurement? Bullet weight (weigh a few bullets, you'll see they vary), case wall thickness and elasticity, case volume, powder measure are all going to have there own percentage and contribution of variance to your overall formula. If you need that kind of "science" (as in Benchrest shooting) you talking a different ball game - (single stage press, competition Bushing dies, annealing, trimming, primer hole work, cleaned brass, consistant bullets etc...) If you have a COL that feeds well in your gun, then consistant case volume/powder ratio is what will have the greatest affect for a given charge and bullet. What REALLY matters here is NOT the OAL but how much empty casing is BELOW the bullet when seated (different bullets lengths and load data will leave different volumes under the bullet), OAL is good way to keep track of that space. Thats why OAL is different depending on the bullet and charge. This is what affects pressure, velocity, accuracy. Otherwise we would determine OAL based on the brand of magazine you use.

[jcmios]

I use a Dillon taper crimp die and it is adjusted to .470 at the case mouth for both cast and jacketed bullets. I have never had a problem with this setting even with very hot loads.

Jim

[Guest Larry Cazes]

As others have said....Just enough to remove the slight bell created to ease bullet seating by the powder funnel and NO more. Neck tension is NOT created with more crimp but must be increased by more resizing. I use an EGW U die to resize .40 cases because I have negative experiences with the LEE FCD and techically it seems to be a bad practice if your using lead or copper plated bullets. I don't have any experience with the LEE FCD and jacketed bullets as I only shoot plated in my SV .40 limited gun.

[Hank Ellis]

A tip I picked up from the "Competition Reloading" video starring the host of this forum.

Back off the crimp die a few turns. Run a fired brass through a properly adjusted decap / size die. Move that brass directly to the crimp die. Screw the crimp die down until it touches the brass. Tighten the jamnut. You're done.

The intent of the crimp die is to remove the belling of the brass and return it to the original dimension of the sizing die. BEnos goes into a bit of detail on crimp theory and the errors that can be made.

I did this when I set up the 550 a few weeks ago and I haven't had to adjust the sizing die since. Verified several hundred rounds with a case gauge and found virtually no rejects. Most of the rejects were due to lube spooge or a lead booger, not due to sizing or crimping.