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Old September 29, 2002, 07:46 PM   #1
Gary H
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Crimping Secrets

Lee's Factory Crimp and Redding's Profile Crimp Die may be your secret to accuracy in a particular caliber, or maybe you don't crimp at all.

What do you use and with what calibers? Why?
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Old September 29, 2002, 07:59 PM   #2
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I just switched to a profile crimp, it's a bit odd in that you can't see much roll crimp on it due to the fact that it tapers first (.357's). I've heard many good things about it, get excellent accuracy as well. Haven't checked velocity SD yet.

I think the theory is that a bit of taper crimp prior to the roll makes sure the bullet is in full consistant contact with the case for good ignition.
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Old September 29, 2002, 11:43 PM   #3
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Can't tell you. Its a secret!




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Old September 30, 2002, 05:27 AM   #4
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I am still using plain taper crimp dies for semi-auto pistols and roll crimp dies for revolvers. I have found that not crimping leads to higher extreme spreads and larger groups.
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Old September 30, 2002, 10:10 AM   #5
Gary H
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With regards to revolvers...Same crimp used with 38 Special as .454 Casull, or 480 Ruger? Same crimp jacketed vs. lead bullets?
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Old September 30, 2002, 10:29 AM   #6
MADISON
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Crimping Secrets

Almost 15 years ago Midway sold 5 TAPER CRIMP dies [uour selection] for $45. I selected 357, 41, 44, 45, 223 and 308. All have served me well.
With a taper crimp you do not have to trim the hand gun brass.
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Old September 30, 2002, 02:52 PM   #7
labgrade
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I dunno about "having to trim handgun brass" ... betcha oe can beat any load by trimming (alhough I've yet to do it - & that after 35+ years) ... still, I betcha you could make it better. Seems that anything adding to extra consistancy would make it better. &, and but, maybe hard to tell in any revolver distance.

I shot a duck once, dead center, at about 650 yards (a .357 cast home=brewed bullet) - somewhat of a fine-tuning of "a load" - a "fine-tuning" that's worked for "a while" in mine.
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Old September 30, 2002, 02:56 PM   #8
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Boy, that duck was sure having a bad day.
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Old September 30, 2002, 03:18 PM   #9
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Secret? Half turn in for magnums, the rest are adjusted till a measurement of the case at the top edge yields the proper width of the case per specifications. Rifles-nothing. I even quit crimping 30/30 after some testing and measurements revealed that the tubular magazine spring pressure doesn't shorten OAL.
I used to be a big fan of not crimping non-magnum handgun cartridges, but some recent chronograph testing has revealed that the fast burning powders seem to like a tiny bit of crimp to get a full burn.
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Old September 30, 2002, 03:41 PM   #10
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Poodleshooter:

Where do you get the specifications for crimp? I have looked but never found anything written about that. Even factory ammo has varge variations between brands.

Thanks for any info, I'm curious about measuring crimp.
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Old September 30, 2002, 09:36 PM   #11
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Steve Smith... "Can't tell you. Its a secret!"

Sure you can tell him, Steve. But then you would have to shoot him...
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Old September 30, 2002, 10:38 PM   #12
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I use Dillon's crimp die because it was included in the set.
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Old October 1, 2002, 04:12 AM   #13
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IMNSLE

As posted first.
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Old October 1, 2002, 05:43 AM   #14
stans
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I tried taper crimping some .357 Magnum ammo, it just did not seem to perform as well as roll crimped ammo.
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Old October 1, 2002, 11:19 AM   #15
john kilgore
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SINCE CRIMPING ISN'T REALLY A SECRET, I'LL TELL !

Most any good reloading manual will tell you about crimping. Try the Speer as it was my first one 30ys ago, and I still reference back to it as some of the material was deleted from newer versions.
For revolvers... With most bullets with a crimp groove, you need to turn the case into the canalure with out crushing the ridges on the bottom of the groove (jacketed bullets). With heavy bullets and slow burning powders in magnum cartridges, use all the crimp you can with out deforming the bullet or "sizing" the case neck into the crimp die. (See Winchester and Hodgdons manuals for recommendation on Win-296 and H-110 -essentially the same powders except lot#'s and labels- both are manufactured by Primex-St. Marks powder facility in St. Marks, Fl).
For Semi Autos, a taper crimp that turns the case neck into the bullet without any more than a thin line where the edge of the case touches the bullet is proper. With SemiAutos, it is emperative that the case be sized sufficiently that the neck tension holds the bullet sufficiently to prevent set back of the bullet upon chambering.
See, no secrets at All. However, some crimp is necessary for max consistency of ignition/Accuracy, except in bolt action rifles.
The Speer manual has an excellent section on crimping/accuracy.
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Old October 1, 2002, 12:01 PM   #16
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The best way for me is to do everything in a single stage, Seat first then crimp, If all is done right you will see it in your chrono and accuracy as well. keep your coal tight, and always trim cases to spec. Aim small hit small. RAMbo.
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Old October 3, 2002, 05:12 PM   #17
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Quote:
Poodleshooter:
Where do you get the specifications for crimp?
For .45 I use the standard dimension for width of the case at the mouth (.472" sticks in myhead for some reason). I do the same for .38, but I forget that dimension. These are for a minimal crimp. For magnums, I ensure that the crimp is below the spec for normal case width @ mouth, and that I have 1/2 turn of crimp on the die body only.
Bottomline, you only need to worry about YOUR specs. Use a good caliper, and measure as close to the top of the case's crimp as you possibly can. Try to stay consistent once you find a good load.
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Old October 4, 2002, 04:20 AM   #18
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Thanks Poodleshooter.
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