357Sig low neck tension

[just for fun]

Ordered 1K of once fired 357 Sig brass and it was all from speer. Because of the high pressure and very small amount of case neck, I keep up with the number of times I reload it. It's retired after 5 times though the press. Ordered from the same place and this time it was mix of just about everybody's brass. Sorted by company and went on my merry way. By 357 Sig standards, my reloads are on the mild side (9MM+p speed range).
Took my son shooting and he had a failure to go into battery! As the slide closed, it sounded "different". Dropped the mag and cycled the slide. The bullet had "slipped" all the way into the case, resting against the powder, with about .060 of the bullet still showing!
Before you say this is an easy one-crimp it some more! Note that my seating die is set just a breath away from collapsing the case shoulder, and I've loaded 6-7K without a hitch. If you reload 357 Sig, then you know what I'm talking about when I say,"I've loaded more than a few (less than a dozen) that didn't feel right (soft) and failed the push to test against the bench test." Passed them off as weak or short brass. These "failures" is what lead to my 5 times reloading max, since they occured at the 4th- 5th time being reloaded. But the last two times I experenced these set back problems it has been with Winchester brass! Second reload, two failures in 250 rounds, and felt good coming out of the crimping die. Has anyone experenced low neck tension with Winchester brass?
Please, don't start on too much crimp for 357Sig's! Asking for inputs on the brass only-not on how to adjust my die.

 

[hAkron]

Are you crimping with a Lee FCD? I love 357 Sig, but I struggle with this round. My thoughts lately are that I'm over crimping and getting spring back of the brass. I'm also using Berry's 124 HP bullets, which I feel are probably a poor choice for 357 Sig. About 1 in 10 fail the push test for me.

 

[OilyPablo]

I'm no expert, but I was going to ask which bullets?

 

[gamestalker]

It hard not to mention your crimp, when it is very likely the culprit causing low neck tension.

GS

 

[918v]

Crimp does nothing for neck tension. Crimp often ruins neck tension. You can't increase tension on a thing by collapsing it. The whole principle of case tension involves slipping something of a larger diameter into something of a smaller diameter. Once the two are married, you can't increase tension by collapsing one against the other because when you collapse one you collapse the other.

First, you need to remove all the carbon from the neck. Carbon acts as a lubricant. It hurts bullet retention. Tumble in wet stainless media.

Second, do not expand the case neck. Flare only. Flare slightly. Get a flare only die.

Third, do not crimp. Remove the bell and let it be. Do not dig the case mouth into the bullet shank. All it will do is ruin case tension. Remember that brass is harder than lead. Brass springs back at a greater rate than lead. When you put a .003" thick jacket around the lead, it still springs back at the rate of lead. It is too thin to affect the lead.

Last, use nickel plated brass. Nickel has more friction on copper than brass. A copper jacketed bullet in a nickel plated case won't move.

 

[just for fun]

hA, I too have found this round very bullet sensitive! Accuracy with Raineir bullets were much more of a pattern type thing. Went to Berry's and accuracy got a "whole bunch" better. Finally broke down and went to Montana Gold and they do everything as well as factory rounds. Oh, BTW that's all I changed everything else stayed the same. These two resent "setbacks" were with Montana bullets. Reading the replys I guess it's going to be a push test for evey round loaded from this point on. Never have, but going to start miking the brass for OAL prior to loading. So that makes two more steps for reloading the Sig round! I do enjoy shooting it, but it sure is a fussy little rascial!

 

[Beanie-Bean]

Hmm...I hope things go better for you. I've been using Dillon's .357SIG dies without issues, and can't really count how many times the brass has been cycled through. I'm usually loading them until they crack. The ones that crack are mostly the nickel-plated variety, and generally happen at Station #2 on my 550, which is where the cases get flared and charged.

I've loaded out Hornady XTP and Speer TMJ in Speer, FC, and Starline cases (no Winchester like you used) and they've all performed well. One thing I do is to run them all through a Redding G-Rx die first. All of my 10mm, .357SIG, and .40S&W brass go through this die before getting loaded. All of those calibers pass case gauge after being sized with it.

 

[Walkalong]

Crimp does nothing for neck tension. Crimp often ruins neck tension.

Very true. Brass is much springier than lead, so the more you push the brass in the more it hurts neck tension. In a round like .357 Sig or .400 Corbon where there is so little neck holding the bullet, this is even more critical.

Check out the diameters in the link, figure case wall thickness in, and it is obvious why the bullet would spin in the case after over crimping.

 

[TfflHndn]

If your main concern is avoiding setback, you might try using A#9 or a similar powder with sufficient bulk to completely fill the case. It will prevent the bullet from setback. Having enough neck tension to allow proper pressure accumulation behind the bullet is another matter, but choice of powder can help with the setback issue.

 

[gamestalker]

Changing to a bulky powder is not a solution to the problem, at all. Back that crimp off to the extent it is only returning the mouth back to normal diameter of the sized neck, maybe .001' - .002" smaller, but no more than that or you will be back at square A. FYI, it isn't the bullet brand or type causing the issue, and changing to a different powder or brass isn't a solution.

GS

 

[OilyPablo]

If the bullet has too much taper, it is a problem.

 

[Peter M. Eick]

I agree with the prior post. The only time I have had poor neck tension on a sig round is when the wrong bullet was tried or the case neck broke.

My Dillon carbide dies are great and snug the brass right up.

 

[gamestalker]

I still feel that " A breath away from collapsing the shoulder" is diminishing neck tension. That will only decrease neck tension for that type of cartridge. Take a cartridge that is clearly lacking neck tension, then re size it, and then seat a bullet in that same cartridge using zero crimp, then try to push it in the case. I would bet on it.
GS