Question on crimp with my dillon dies

[Brian1911]

I have loaded well over 20k rounds and didnt buy a bullet puller until recently and made a discovery. On my FMJ rounds I noticed they are mushroomed a bit after going through the crimp station. I mean the top half is now larger then the bottom half which was seated inside the case. My crimp has always been .469-.470 which I understand to be normal for 45acp.

So is it normal for the copper on a FMJ bullet to smash like that or should i back my crimp off even more?

I did test the amount of case tension on these rounds and even on a case that I didnt run through the crimp station I had to wack the heck out of it in the bullet puller to get the bullet out. So I trust that the first station is doing its job of resizing the brass enough to properly tension the bullet.

Update:

I just backed crimp off to .471 and still there is a slight amount of copper smashed at the bottom half of the bullet. I called Dillon Tech and was told that I dont need as much crimp if this is what I am finding. I guess the number doesnt matter so much as it does looking at the bullet and testing to see if the bullet wants to set back at all. So I guess I will back off a bit and test a handful then see what happens.

Edited December 1, 2009 by Brian1911

[High Lord Gomer]

I was having trouble with my crimp cutting through the plating on the Berry's plated bullets. I read that it should be enough to crimp just enough to take the flare out of the case, so I now use a micrometer and verify that the diameter at the mouth of the case is the same or .001" less than the diameter at the base (or middle) of where the bullet has seated in the case.

[Singlestack]

The crimp die should be used to remove flare. It sounds like you are way over crimping.

[Brian1911]

Thanks guys. It seems that .469 isnt the standard and it depends on what the ammo tells you. In my case .469 smashes the FMJ and makes it look mushroomed so I will back it off.

I was able to go to .471 and could very lightly see that the FMJ was pressed in but nothing like it was at .469. I will try to back off a bit more then chamber check the rounds until I get my case gauge.

[Sarge]

Thanks guys. It seems that .469 isnt the standard and it depends on what the ammo tells you. In my case .469 smashes the FMJ and makes it look mushroomed so I will back it off.

I was able to go to .471 and could very lightly see that the FMJ was pressed in but nothing like it was at .469. I will try to back off a bit more then chamber check the rounds until I get my case gauge.

Your chamber is the best gauge you can get. My gauge is now laying in a tool box somewhere after some rounds that passed through it would not fit my chamber.

[A63111]

Try measuring your brass/bullet below the flair.Then set the crimp to approx. .001 less at or just below the case mouth.

[Brian1911]

Try measuring your brass/bullet below the flair.Then set the crimp to approx. .001 less at or just below the case mouth.

Do you mean I should measure around where the bullet is in the brass? Either way I will have to take a measurement as close to the end of the case as I can to find what the crimp is right?

Basically as I start to adjust for this I am going to back the die out and keep running the brass though until I can feel no more flare and find a measurement that is the same as where the bullet is in the brass. If anything maybe taper down .001 more then that like you said.

Is this what you were saying?

[Hi-Power Jack]

Try measuring your brass/bullet below the flair.Then set the crimp to approx. .001 less at or just below the case mouth.

Probably oversimplistic, but I couldn't take these precise measurements

either, so I just adjusted the crimp so the rounds would feed, and the

rounds were accurate in my gun - I've never looked to see if the

bullets are being "crimped" too hard. Long as they go bang and

hit where I want, I'm happy:)

[Brian1911]

Well so far I am learning there is no way to remove all the crimp so that the bullet has no signs of having been loaded. I started at this point but the round would stick in my match barrel and I would have to shake the gun for it to fall back out. At this point I made small adjustments to tighten the die until the round would fall in and out freely then inspected the bullet. What I found is there is still a very slight mushroom affect and you can barely see it but it can be felt with your finger.

I shot more then 20k rounds with more crimp then I apparently needed and had no issues so if anything perhaps spending this time to eliminate deformation of the bullet will give me more accuracy but I doubt it will be noticed.

So are any of you guys able to pull a bullet and not see any sign it has been loaded? Or can you feel or see just a slight ledge along the side of the bullet right where the brass would stop when it was together?

[gm iprod]

If the case has a square edge on the mouth, any and I mean any, crimp will leave a mark. Too mouch drimp will indent into the projectile. There is a huge difference between a mark and being "ringed".

If you chamfer the case mouth about 0.010" with the correct tool. you can reduce this mark substantially. BUT you should also trim all your cases to be sure that the mark is even and minimalised.

Once you have done all your cases, we will send the big white van and burly nurses around to collect you.

Adjust as previously suggested and stay sane.

My 45ACP rounds made on fairly new brass leave the tiniest crimp mark around the 185JHP Zero that I use. Never loaded Plated in the 45, had better results with JHP in 38super and 9mm, so just could not be bothered with them in anything else. I use Polymer coated SWC when I need cheap ammo.

Have a nice one

edited for spelling

Edited December 4, 2009 by gm iprod

[A63111]

Try measuring your brass/bullet below the flair.Then set the crimp to approx. .001 less at or just below the case mouth.

Do you mean I should measure around where the bullet is in the brass? Either way I will have to take a measurement as close to the end of the case as I can to find what the crimp is right?

Basically as I start to adjust for this I am going to back the die out and keep running the brass though until I can feel no more flare and find a measurement that is the same as where the bullet is in the brass. If anything maybe taper down .001 more then that like you said.

Is this what you were saying?

That's what you should be doing. Another thing to look at as others stated is your brass. I purchased some range brass once that had been ever so slightly deformed in the case mouth. As others stated brass could be an issue. You should not have to deform the bullet to get the proper crimp. Yes you are measuring properly, that should be bullet diameter plus the thickness of you brass times 2. .470 should be very close. Try taking something like a small (precision) screwdriver and feeling the inside of the brass for any deformity.

[Brian1911]

Thanks guys.

Well this is on 45acp so I am not going to worry about brass trimming or anything like that. If it were rifle then maybe I would go through all of that but I only load 45acp.

I think I have it pretty close to perfect but as mentioned there is really no way to not leave a mark on the FMJ after crimping. I was able to reduce crimp from .469 to about .470-.471 and now the bullet looks better but I fear I am on the edge of reliability. I think I will add a touch more crimp to get it back to .470 and just live with the mark on the bullet.

I would take a pic but it really is not that noticeable but it can be felt when you run finger along the bullet. I cant imagine you guys are able to crimp and not find any mark on the bullet but there really isnt much more I can do with out the rounds becoming unreliable.

Edited December 4, 2009 by Brian1911