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Old August 12, 2009, 05:20 PM   #1
cobia1966
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.45 crimping?

Hi all
I'm fairly new to reloading and have a question about crimping a .45 acp. I'm having a problem with my bullet getting pushed further into the case when the slide goes forward, i.e., 1.26 OAL to 1.211 OAL. I'm thinking its the crimp and want to adjust it, but how do I know if I crimp it too much? Also, what happens if you shoot a bullet thats been crimped too much? I'm using the Lee factory carbide crimp die, if that matters. Also, I'm now shooting a Kimber TLE Custom 2. This problem also happened out of a Taurus PT 1911 and a Colt 1911.
Thanks for any input
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Old August 12, 2009, 05:32 PM   #2
AK103K
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I use a taper crimp on most of my handgun rounds. It works like it sounds, and doesnt roll the case mouth. Guns like the .45acp headspace on the case mouth, so you really dont want to roll it.
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Old August 12, 2009, 05:38 PM   #3
Nnobby45
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The spec for case mouth diameter is .471 or .472. Lead needs to be crimmped a little more to .469 or so. If you have one of those silly dies (that Lee seems to like) that roll crimps the bullet into the case, then your diameter right at the mouth will be smaller.

Once your TAPER crimp die is set to produce that dimension, you have the crimp you need. Too much taper crimp can deform the bullet and actually loosen things up. It's the bullet tension produced by the sized case that holds the bullet. The purpose of the die is to restore the case mouth so it's straight, though a proper crimp should reinforce the tension a little.


Take into account the different lengths of "range brass" if that's what you're using. Adjust flare for the shortest so you can seat a flat based bullet. That way it's set even if you use bevel base bullets.

Neither under or over bell (flare, expand) the case mouth. No need to be one of those folks who "flares just barely enough to seat the bullet". Flare enough so you don't crush the case when seating the bullet, then flare a little more to eliminate lead or copper shavings.

What happens when you test your loaded rounds by pushing them against the bench kinda hard? Do they slip then?

Nothing bad happens if you shoot a round with excessive crimp.

The Test:
measure a SIZED case about in the center of where the bullet would be. Measure the loaded round in about the same place. If you have about .004 difference (.004 worth of tension), then your case is sized enough.

For examle, I just measured a Winchester case at .466 sized on my Dillon 550B. Loaded it was .470. The difference between loaded and sized rounds equals the tension with .004 being adequate. Maybe .003 would be ok, not sure. Use the bench test.

And last, you can learn a lot by studying the dimensions of a factory round.

Last edited by Nnobby45; August 12, 2009 at 05:58 PM. Reason: make english more better
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Old August 12, 2009, 05:42 PM   #4
cobia1966
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.45 crimping?

Yes, they do slip when pressed hard against the bench. By the way, I'm using 185gr. flat nose Ranier lead safe bullets.
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Old August 12, 2009, 06:15 PM   #5
drail
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Try this. Seat a bullet without applying any crimp/ Now press it hard against the bench. If it moves into the case then you have insufficient case neck tension. In other words your expander die is over expanding the resized case. Remove the expander plug from the die and measure its diameter. It needs to be .0015 to .002 thous. smaller than whatever bullet diameter you're using. If your expander plug is oversize it can be turned down in a drill or drill press until it is sufficiently undersized. If the resized and expanded case is not gripping the bullet tightly then NO amount of crimp will fix the problem. On an ACP case the crimp only serves to remove the flare so that the round will chamber easily and then headspace (theoretically) on the case mouth. Heavy crimping to attempt to stop setback is a waste of time. Case neck tension is maybe 80% and crimp is maybe 20%.
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Old August 12, 2009, 08:25 PM   #6
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Cobia,
The .45 ACP uses a taper crimp which merely removes the belling of case mouth that was done to facilitate bullet seating. Bullet is retained and setback prevented by SIZING the case before charging with powder and seating bullet. Are you properly sizing your cases? Details? Measure diameter of case mouth BEFORE sizing and AFTER sizing, then AFTER seating bullet and taper crimping. This will give us more info to help you debug your problem. As mentioned in prior post, your expander plug may be over-expanding the body and removing the sizing which is required to prevent bullet setback.
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Last edited by LHB1; August 12, 2009 at 08:54 PM.
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Old August 12, 2009, 08:30 PM   #7
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moving to the reloading forum
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Old August 12, 2009, 09:00 PM   #8
cobia1966
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Thanks for all the advice. I'll check the sizing die and do some measurements and get back with more info.
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Old August 12, 2009, 09:50 PM   #9
Kyo
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i reload lead and my neck sizes come out to .470
they shoot fine in my gun
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Old August 12, 2009, 10:26 PM   #10
drail
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The critical test for this is to see if the bullets are being gripped tightly by the case mouth after you expand it and before you crimp it. I have seen more than a few die sets that will resize to proper spec and then overexpand the mouth until it doesn't hold the bullet. If you can push it back into the case this is your problem. So many people assume that cartridges for a semi auto will setback when feeding and that's just the way it is. Not so.
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Old August 13, 2009, 12:03 AM   #11
Nnobby45
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Quote:
Yes, they do slip when pressed hard against the bench. By the way, I'm using 185gr. flat nose Ranier lead safe bullets.
Couple of things: Lead bullets should be .452. You might check.

If the bullets are soft cast, they provide less tension.

Lead bullets generally have a groove filled with a type of lubricant. The cut made by the groove would be subtracted from the amount of bullet that actually contacts the case. If it's a bevel base bullet, the beveled portion also does not contact the case.

Check and see how much of the bullet actually contacts the case to provide tension, and you might be surprised at how little there is.

Generally a 200 gr. bullet has enough lead in contact with the case to provide tension, even with lube cuts and beveled base.
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Old August 13, 2009, 03:32 AM   #12
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I'd echo what has been said and encourage you to check your expanding die out in particular. I just got done troubleshooting the same problem which I traced ultimately to an out of spec expander die. The expander plug wasn't properly tapered and thus was over expanding the brass and providing inadequate neck tension. If you suspect this might be the case, then you can always remove the plug and measure it to check. It should taper slightly so that it is narrower than the bullet at one end and gets progressively wider. If it is wider than the bullet at the narrowest point, then that is probably your problem as was mine.
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Old August 13, 2009, 07:58 AM   #13
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Agree with...

It sure sounds like an expander die issue, or else a resize die that isn't properly set in the press (?).

I shoot all jacketed bullets, but I never have crimped (rolled) a .45 - or 9 for that matter.

Hope you work it out and welcome to the hobby!

God bless.

Margiesex

And remember: Hug your God and your guns - 'cause he's coming for them both, and soon!
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Old August 13, 2009, 09:43 AM   #14
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Ther seems to be some confusion about the Lee FCDs for handgun cartridges. They don't work on the same principle as those for rifle cartridges, which are an indentation forming collet die. The FCDs for handguns use a ring insert that controls the crimp profile. This ring provides a taper profile in the dies intended for auto-loader cartridges, and I understand (don't happen to have one) a roll crimp profile in those intended for revolver cartridges. The only difference their .45 ACP FCD die has in comparison to a standard taper crimp die is the carbide OD sizing ring the finished round passes through. It is intended to guarantee a diameter that will feed properly. All their handgun cartridge FCDs have those rings.

The same neck diameter that holds a jacketed bullet hard often will not hold a lubrictated lead bullet adequately. I always set the taper crimp to dig into the lead a few thousandth to form a step in the bullet for that reason. It jams it from backing up without shaving lead (though if you push hard enough, it will shave lead). Just adjust the crimp until it doesn't back up from feeding forces. That is enough. The SAAMI drawing shows the cartridge OD at the mouth to be 0.4730"-0.006". In other words, 0.4670" to 0.4730" is the acceptable range, which gives you quiet a bit of taper crimp wiggle room with cases that have a thick wall.

The hazard in overcrimping the rimless auto-loader pistol rounds would be a cartridge case mouth slipping into the throat of the barrel and refusing to let go of the bullet when it fires. That would create a serious overpressure condition. That's the reason for the OD minimum on the loaded round at the mouth, since the .45 ACP is supposed to headspace on the case mouth. In reality, however, most chambers are long enough that the cartridge headspaces on the extractor hook of the pistol before it gets that far forward. Back in the 60's, when the NRA still published the technical details of loads used by champions, you found most were shooting H&G 68 type 200 grain SWC bullets protruding 0.020" from the case and roll crimped hard to hang onto the lead. This would not be possible if the case mouth were going into the throat. It isn't good for brass life, but lots of careful study was done to show it was, indeed, the most accurate cast bullet ammunition they could come up with at the time.

I use a slightly different approach. I seat lead bullets out until they touch the throat so the cartridge headspaces on the lead bullet itself. That does not work with round nose bullets in guns with long chambers or deeply throated barrels because the cartridges can get too long to fit the magazine. But for most guns it works fine. It keeps the case mouth away from the throat, so I can crimp as narrowly as I please without worry, or even roll crimp if I choose to. It also keeps the cartridge from touching down on the extractor hook and being tipped sideways in the chamber on firing, which harms lead bullet accuracy (jacketed bullets don't seem to mind). Finally, the method puts the bullet out far enough that even if it did push in slightly, no pressure issue would arise.

I hit on that method in the mid-80's by experimentation, but subsequently learned it was being done by many others, as well. It cut group diameters for the 185 grain swaged lead Star bullets I was shooting in gallery loads substantially. I forget the numbers, but I think I tested them at 25 yards (even though I only shot them at 50 feet in matches) off bags, and I recall groups of about 1 3/8", where they had been more like 2 1/2" before seating out. The stubby soft 185's were hard to load for accuracy and they leaded the barrel easily. But both problems were improved by seating the bullet out like that. See third from left below.

Note the red slash circle signs are advisories against poor lead bullet accuracy at the left end and poor feed reliability at the right. They are not about danger.

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Last edited by Unclenick; August 13, 2009 at 10:01 AM.
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Old August 13, 2009, 11:11 PM   #15
Nnobby45
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Quote:
...... The expander plug wasn't properly tapered and thus was over expanding the brass and providing inadequate neck tension. If you suspect this might be the case, then you can always remove the plug and measure it to check.
No disagreement, but imagine how simple it is to measure the difference between the sized and loaded round to see if you have an adequate .004 or so.
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