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Old August 30, 2009, 10:38 PM   #1
Kels73
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Is taper crimp acceptable for .357 magnum loads?

I'm new to the forum, so I want to say a quick "hello" to everyone. I'm also new to reloading and have a concern that I'm hoping someone can help me with. I recently purchased a set of RCBS carbide reloading dies for .38/.357. Unfortunately, I purchased the taper-crimp set instead of the roll-crimp set. Do I need to get the roll-crimp set, or is taper-crimp sufficient? I reload for a Blackhawk and like to make, both .38 spc. target loads and full-power .357 magnum loads for hunting. I purchased the die set from MidwayUsa, so I suspect that returning it won't be too hard, but I still want to pose the question so that I can learn more about the issue of crimping.

Thanks,
VTShooter
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Old August 30, 2009, 10:49 PM   #2
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A firm crimp for full power loads in magnum revolver loads was recommended in the manuals I have read..... something about bullet set-back from recoil and/or inconsistant ignition/burn of large powder charges due to variations in pressure needed to start the bullet moving, IIRC.

I never questioned it and used a firm roll crimp for all my .357 loads. It worked.
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Old August 30, 2009, 10:58 PM   #3
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For heavy loads with heavy bullets, 'bullet pull' can be a real problem especially with a comparatively-light revolver. I've used both and I prefer a roll crimp on such loads.
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Old August 31, 2009, 07:33 AM   #4
SL1
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I use both for different .357 Magnum loads.

The roll crimp is necessry for your heavy hunting loads. With heavy loads, the recoil makes your gun act like a kinetic bullet puller, and bullets that are not crimped tightly enough can pull out of the case far enough to stick out the front of the cylinder a little. Once a bullet gets out of the cylinder more than the barrel-to-cylinder gap, the cylinder can't turn and your gun is "tied-up". Not a good situation in the hunting field or a self-defense situation.

On the other-hand, I use the taper crimp die for light loads where bullet pull-out is not a problem and the bullets do not have a crimp groove in the appropriate place. That includes soft-swaged wadcutter bullets (which I seat out just far enough to get the bullets into the chamber throats to improve initial alignment), plastic Speer shot capsuls, and various cast and plated bullets that were designed for other cartridges and do not have crimp grooves where I want them.

So, unless finances are limiting, I would suggest keeping your taper crimp die and buy a roll crimp die too.

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Old August 31, 2009, 08:15 AM   #5
Alleykat
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Lee roll-crimp FCD!
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Old August 31, 2009, 08:17 AM   #6
margiesex
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Roll crimp all the way...

Since I've been rolling my own - I roll crimp - pretty severe, too - my .357 loads of 15 grains of 2400 pushing a 158 grain JSP.

Never had a problem.

God bless and good shooting.

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Old August 31, 2009, 10:18 AM   #7
drail
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Yes it's acceptable but if you make sure that your expander plug in your flare die is leaving the case mouth 2 or 3 thousandths under your bullet diameter you will have enough tension on the bullet that heavy crimping is not necessary. Trying to control bullet pull or setback with just a heavy crimp is an exercise in frustration. The case mouth needs to have a tight grip on the bullet before you crimp the round. Without it the bullet can move and crimping heavier will not hold in place. Measure your expander plug and if it's oversize chuck it in a drill and turn it down. Heavy crimping will workharden the case mouth over time and reduce case life. Roll crimping is really designed to be used on bullets with a cannelure to crimp into. Taper crimp is for jacketed bullets that have no crimp groove and will be used in an autoloader that headspaces on the case mouth. But you can use either.
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Old August 31, 2009, 10:29 AM   #8
SL1
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I am going to have to disagree with drail on that. A strong roll crimp has a much greater effect on bullet pull-out than case-neck tension does. True that you can get a lot of bullet grip with case mouth tension, but heavy .357 Magnum loads with large charges of slow powders will ignite more uniformly and resist bullet pull-out effectively with a strong roll crimp.

On the other-hand, in my experience with light charges using fast powders, a taper crimp can give better uniformity and accuracy for target loads in the same cartridge.

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Old August 31, 2009, 10:31 AM   #9
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Welcome to the forum.

I shot wadcutters loaded in .357 cases over 3 grains of Bullseye in bullseye revolver matches for a number of years. Long case life and no bullet pull issues with the light loads. The gun was a Dan Wesson 15-2, so it had some heft. The taper crimp did a good job under that circumstance, but if the load is increased or the gun is light, either one can start the bullets coming out.

As an extreme example of bullet pull, a friend of mine got one of those titanium snubnose .45 Colt revolvers, and it cannot fire any 250 grain bullet in commercial or reloaded ammo. The frame is so light that the recoil just yanks back on the loaded round rims so hard, the bullets pull our inertially. 200 grain bullets are his upper limit in that piece. No amount of tight case sizing or roll crimp fixes it. And this is a big guy with hands that make a can of Foster's look normal size, so it is not a grip issue.

If you are going to shoot target loads, take advantage of the taper crimp to get long case life. Take AlleyKat's suggestion to get the separate Lee Factory Crimp Die in .357 to do the roll crimps for your heavy loads. It's inexpensive. This way you'll have both crimp styles available to you for both purposes.
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Old August 31, 2009, 04:35 PM   #10
MADISON
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Taper Crimp and a .357 Magnum

I have been Taper Crimping my:
.38 Specials
.357 Magnums
.41 Magnums
.44 Magnums
.45ACPs
for over 20 years. There have been no bullet slippages.

A Taper Crimp is nothing but a sizing die with the primer decapper removed and the die readjusted.
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Old August 31, 2009, 08:07 PM   #11
Kels73
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Thanks, everyone.

I'm glad I took the time to pose the question. I have definitely learned a lot about the matter. I've decided that I'm going to keep the taper-crimp die and order the Lee Factory Crimp Die.

This has been very helpful. I'm glad I joined the forum.

VTShooter
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Old September 1, 2009, 06:26 AM   #12
WESHOOT2
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Even better......

Best is the superior Redding Profile Crimp Die, which starts with a gentle symmetrical 'taper' (and can be adjusted to apply only that) and finishes with a superb and symmetrical 'roll'.

Tested to both enhance ballistic uniformity and accuracy.
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Old September 1, 2009, 08:42 AM   #13
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I agree that the Redding "Profile Crimp" die makes nice roll crimps, without bulging the case below the crimp. I prefer it to the Lee "Factory Crimp Die" because it does NOT have the carbide ring that sometimes swages the bullet a little when using larger bullets, such as cast lead.

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Old September 1, 2009, 02:07 PM   #14
Kels73
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I'll be sure to take a look at the Redding die, also. Thanks again, everyone.
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