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Crimp advice, please.


BentAero

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20181216_172252_zpsxovwmyho.jpgMy first taste of Bayou Bullets 145 gr RN. Seating/crimp combo die is a Hornady.

 

1) See the faint crease-line on the nose from the die? Does my case expansion/flare need to be larger? i.e is it taking too much force to seat the bullet hence it's causing the crease? Does it matter? Don't worry about it? I noticed the same thing on Gallant coated, but not Acme.

 

2) I'm assuming the crimp is too tight, which is causing the cut line in the coating?

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Yes, too much crimp. Never want to cut the coating. If you have the stations available I would suggest seating and crimping in separate steps. Lee makes a good taper crimp die very cheap, not the factory crimp die as that die often causes other problems with coated lead. 

 

As as for the ring on the nose, it probably isn’t going to hurt anything, but measure the bullet you pulled to make sure you haven’t swaged it down. 

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1 hour ago, BentAero said:

 

 I'm assuming the crimp is too tight, which is causing the cut line in the coating?

 

We don't actually "crimp" 9mm, just remove the belling - straighten the case back out.

 

If you fire a bunch of those, you'll probably be disappointed with the accuracy.     :) 

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3 hours ago, Hi-Power Jack said:

 

We don't actually "crimp" 9mm, just remove the belling - straighten the case back out.

 

If you fire a bunch of those, you'll probably be disappointed with the accuracy.     :) 

A bunch of those -as in Bayou? Or a bunch of those as in "crimped" like the photo?

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6 hours ago, BentAero said:

A bunch of those -as in Bayou? Or a bunch of those as in "crimped" like the photo?

"as in crimped like that"  Bayou's shoot great.

But no coated bullets works well with a heavy crimp like that.

Back your crimp die off to just straighten the bell out or appox. .001 under.

Mine plunk/case gauge much better with the crimp set at .001-.002 under

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For the record the Hornady seating die will leave that size ring on coated and soft plated bullets.  The Dillon die leaves a much smaller one near the apex/tip of the bullet and neither will not effect anything more than looks for sub sonic loads. Both dies are correct for RN bullets. 

 

The crimp is too much, as everyone will contend. 

 

You didn’t state which die set you use but the answer for crimping should include “taper” in its description. For 9mm I have found the Dillion taper crimp die gives the smoothest cleanest “crimp” amongst the three I have used (Lee, Hornady, & Dillon).

 

Part of the fun of this hobby is finding the perfect load for you gun. You’re on the right track. 

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Some people will say that 9mm doesn't need any crimp and others will say that the crimp should measure .001 - .003, but the important thing is that you're not cutting the coating. Luckily, 9mm is pretty forgiving with crimp so even if you don't have an extra station to crimp separately, you should be able to back off the crimp until you're just removing the bell of the case and still have consistent ammo.  The same cannot be said for some other calibers.

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I run minimal crimp as determined by the OUTSIDE diameter at the bullet end of the brass.  Out of my gun, the best accuracy is found when that measurement is 0.3795 to 0.3805.  Going down to 0.3780 increases groupings at 35 yards from 3 to 6". 

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I seem to remember that the crimp should measure .376. If you put a factory round in the shell holder and back off the crimp die a bit you can set the crimp to factory specs. Bayous shoot great and so will your ammo after  a bit of tweaking. (Not twerking!) LOL

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Thanks everyone, I appreciate your wisdom. I haven't loaded any of the Bayou yet for firing purpose. The photo was a test of seating starting point of a Bayou with the die still set for Acme 135 RN from the previous run. With a clean shell plate it measured 1.157" so it was out there a bit.

The several Acme 145 and 135, and Gallant 147 bullets I've pulled never had anywhere near that much coating cut.

I'll adjust and assemble a few rounds for chrono testing around Christmas.

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The crease you're experiencing may be caused by using a seat/crimp die.  The bullet is still moving into the case as the crimp is applied, resulting in some scraping of the coating.  If you were to seat and crimp in two separate operations, as suggested earlier, the crease may disappear.  Try seating a few bullets in your current die without any crimp; back out the die completely until there's no crimp at all, then screw in the seating stem until you get your preferred overall length, and seat the bullets. Then back out the seating stem and readjust the die to crimp only and run your cartridges back through the die.   You may be surprised with the results. YMMV.

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I shoot bare swaged lead 

On 12/17/2018 at 1:27 PM, Dr. Phil said:

I seem to remember that the crimp should measure .376. If you put a factory round in the shell holder and back off the crimp die a bit you can set the crimp to factory specs. Bayous shoot great and so will your ammo after  a bit of tweaking. (Not twerking!) LOL

 

There is no such thing as factory specs for a caliber.  Different manufacturers, different specs.  Different components from same manufacturer, different specs. 

 

.376 is too narrow for. 356 coated lead. 

 

 

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On 12/20/2018 at 1:15 PM, Dr. Phil said:

 Never said there was a "factory" spec.

 

Um... ;) 

 

On 12/17/2018 at 1:27 PM, Dr. Phil said:

 If you put a factory round in the shell holder and back off the crimp die a bit you can set the crimp to factory specs. 

 

I think you sorta kinda did.  ;)

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Yep I kinda did LOL.

So I measured some of the factory stuff I have on hand, at the crimp.

 

Federal  .3755

 

Black Talon   .376  (Win cases)

 

Winchester   .3765

 

Blazer   .3755  (FC cases)

 

Seems like a great place to start setting the crimp.

(I kinda said that too 😀)

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2 hours ago, Dr. Phil said:

Yep I kinda did LOL.

So I measured some of the factory stuff I have on hand, at the crimp.

 

Federal  .3755

 

Seems like a great place to start setting the crimp.

(I kinda said that too 😀)

 

Which Federal load was that? For the purpose of this thread (coated bullets), I think the factory load most likely to be a relevant comparison would be Federal Syntech.

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Nope. 125gr fmj. The original questions in the thread were referring to, does the crimp line in the bullet matter, etc. I think a crimp line that doesn't cut the moly coating does not matter. But maybe that's just me...

Would be interesting to pull a Syntech and see if there is a crimp line tho.

I also don't see that the OP shot any of these. Maybe they shoot fine?

Worth checking out.

Edited by Dr. Phil
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6 hours ago, Dr. Phil said:

I think a crimp line that doesn't cut the moly coating does not matter. But maybe that's just me...

 

Given that the photograph isn't perfectly focused, it's hard to be sure, but it looks to me as though the coating may have been cut - the ring around the bullet looks metallic to me.  I agree that it would be interesting to pull a Syntech round to see what it looks like.  I'd volunteer to do it except that I only ever had 200 rounds of the 115 grain stuff that I got from the prize table at a match about a year and a half ago, and it's long gone.

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12 hours ago, Dr. Phil said:

 

 

Seems like a great place to start setting the crimp.

(I kinda said that too 😀)

 

What a factory crimps to .355 jacketed bullets to is not what you want to crimp .356 coated lead to. 

 

Bad place to start.  ;)

 

 

 

 

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