7mm STW Brotherhood - For those who shoot the 7mm Shooting Times Westerner

[Lefty7mmstw]

Another new guy question.
I'm getting lateral thinning and splitting about 1/4" ahead of the belt on my cases. Internet search pointed to excessive headspace allowing the front of the case to move forward, while the base is held by the extractor, thinning the case as it stretches.
All these cases have been shot before and were in excess of .005 headspace. All these cases were bumped and measured at .005 prior to this last shooting episode, where they showed signs of cracking.
You guys told me .003 was where i needed to be but I couldn't get my dies to repeat at .003 and the press "settled in" at .005 so that's where I left it. The bump seems to be dependent on the initial case shoulder length and I'm seeing +- .001 coming out of the gun.

So, does your experience suggest the .005 and greater headspace is the reason for the lateral splitting?
I have noticed the area where the cracks or shiny rings appear is where the full length sizer is working the mtl.
(pics were from the article, but a cpl of mine look like that. Most were verry thin cracks w/ no powder ring)

All casings will eventually fail. How many firings are you getting? Did you smoke the shoulder of a fired round to find where your die is pressing onto the fired case?
I usually set the dies so the round will just chamber, and don't even bother trying to find the bump-back.
Hot loads(heavy bolt lift) will add to case stretching because everything is pushed outward harder. More case taper also adds to this; my brother's 300 h&h is killing cases at 4 times fired or so.
I'm in the process of culling 100 reformed 375h&h that were fired 2-3x as h&h and then converted to 7stw when I sold the h&h. they all lasted another 2-3x as 7stw. They are all showing the tell tale bright ring by 6x fired.

 

[WapitiBob]

these cases are in the 6-8 times fired. The necks were getting harder than the back of my head so I have started annealing them. I figured they would eventually give up.

I smoked the shoulders and I now have the die set at .002 to .003 and it appears to be repeating there.

 

[Dano1]

these cases are in the 6-8 times fired. The necks were getting harder than the back of my head so I have started annealing them. I figured they would eventually give up.

I smoked the shoulders and I now have the die set at .002 to .003 and it appears to be repeating there.

6-8 firings on Nickel plated cases is actually pretty good. I could only get 5 firings out of Nickel plated Remington brass out of a 7mm Rem Mag that I had. I don't like the stuff and only use Standard brass now.

Nickel brass also work hardens much quicker as well, so you are doing the right thing by Anealing the remaining necks.

Dan

 

[WapitiBob]

std Rem brass

 

[Dano1]

std Rem brass

Sorry Bob, just realized that the photo I was seeing was black and white. Looked like Nickel brass to me.

That being the case..... They should definately be lasting much longer. I'm supprised at the work hardening and the thinning as well.

Does sound like excessive head space, and that it was headspacing on the belt, not being held in place by the extractor as in standard beltless cases.

Setting it at .002 should take care of the issue, but from this point on I'd check all of the brass to make sure that they aren't about to fail as well. New Brass won't separate now that you've figgured out the shoulder bump issue, but I'd keep an eye on the older stuff for sure.

Dan

 

[7stw]

Hey dudes, I just wanted to pass along a little something that I came up with, that is giving me amazing accuracy, and really good case life.
I came up with a idea, as to make a neck sizer die, that actually checks the body JUST A TOUCH, and the neck of course. So, I have a miriad of dies in my cabinet. I picked out a set of 7 mag dies, backed off the lock ring, and ran a 7stw case up into the die until I feel it bottom out. Lock the ring, and pretso' instant neck size die, that just kisses the body. The die that I am using is a RCBS fl die. What I do is put a case in the shell holder, run it to the top. Screw the die down until you can not go any farther. This should be the top. You can tell by the mark it leaves on the neck. Chambering is sweet. It has that perfect fit feeling to it, when you close the bolt. This die will contact all but the case head. It has worked wonders for me, and I just wanted to pass it along. I have been using it for a while, but wanted to work it for a while before I passed it along. I have used it on my two latest additions, and the both have shown response to it. Great case life. And a nice feel when you chamber. Albeit, you will have to at some point F/ L resize, to squeeze in the case head area a little, and then start over again with the NS die. I believe that it could ALMOST be set as a shoulder bump die, but the whole case is not being supported. I will think about that a little more first.
Take care guys, hope all is well. Two more weeks, then it's vacation, and crop damage control. Got a couple of " items " to break in!!!!!

 

[7stw]

std Rem brass

Man, you have got some funky {]{^£> going on. You have clearly got a headspace issue going on, OR, you are pushing the shouted back TOO far when you resize.
I have a very serious suggestion. Take two once fired cases, and your dies, and send them to the manufacture of the. I don't know if they are RCBS, or whoever. They will mic the dies you have, and compare the case. They will then custom grind your dies to YOUR case, which is a mold of YOUR chamber. It is possible that the chamber in your gun is extra generous, and the case is stretching a lot when you fire. When you are resizing, you are pushing it all to the base, which is the weakest point on a belted mag anyway. It gets work hardened, and then splits. You DO NOT want to blow a case head in a case that big. Those pix are scary!!!!! I would be curios to see a chamber mold of that gun, and compare to SAAMI specs. Hmmmmm!

 

[7stw]

std Rem brass

In reference to my first post, I just realized those were older cases that you WERE having problems with, BEFORE you made the change. If that is true, dis regard my last post, but by all means, at least take heed to the implications, and what happens when belted mag cases are not sized properly. Enjoy, and do be safe.

 

[WapitiBob]

Yea, these have been bumped back by .010 at least, when I first started.
What I would really like is a neck die that bumps the shoulder, then a match grade seater.
I still have 130 new cases so I will start from scratch tomorrow.

 

[ButterBean]

std Rem brass

Bob, You have some serious issues there And the wheels are about to come off of it ......With all of the brass trouble you are having Im gonna second 7stw in thinking you have a chamber thats about maxed out....... and he is right about having custom dies ground but you are at a point that you need to do sonething before you have a case faliure......nothing good comes out of that ......just dont wanna see you get hurt

 

[etisll40]

BRASS,

There's some Remington on Gunbroker.

I can get quantity from my supplier if anyone needs it. Remington 7mm STW of course.

Anyone get more firings from Nosler than Remington? 25 count for $50 bucks is like 100 cases for $200. No deal there, unless it lasts twice as long as Remington.

 

[Dano1]

Hey dudes, I just wanted to pass along a little something that I came up with, that is giving me amazing accuracy, and really good case life.
I came up with a idea, as to make a neck sizer die, that actually checks the body JUST A TOUCH, and the neck of course. So, I have a miriad of dies in my cabinet. I picked out a set of 7 mag dies, backed off the lock ring, and ran a 7stw case up into the die until I feel it bottom out. Lock the ring, and pretso' instant neck size die, that just kisses the body. The die that I am using is a RCBS fl die. What I do is put a case in the shell holder, run it to the top. Screw the die down until you can not go any farther. This should be the top. You can tell by the mark it leaves on the neck. Chambering is sweet. It has that perfect fit feeling to it, when you close the bolt. This die will contact all but the case head. It has worked wonders for me, and I just wanted to pass it along. I have been using it for a while, but wanted to work it for a while before I passed it along. I have used it on my two latest additions, and the both have shown response to it. Great case life. And a nice feel when you chamber. Albeit, you will have to at some point F/ L resize, to squeeze in the case head area a little, and then start over again with the NS die. I believe that it could ALMOST be set as a shoulder bump die, but the whole case is not being supported. I will think about that a little more first.
Take care guys, hope all is well. Two more weeks, then it's vacation, and crop damage control. Got a couple of " items " to break in!!!!!

This is actually a good idea for neck sizing a case. I've used a similar method when forming the first cases for 6.5-06 brass prior to having a 6.5-06 AI built so I could proof the gun and chamber. I necked down .270 Win Brass by using a .260 Rem FL die.

I have 3 sets of 7mm Rem Mag dies, so I will set one up to try this as well. It certainly couldn't hurt.

Dan

 

[etisll40]

Some good posting going on here, we all should be listening in. This subscription has a lot to offer. thanks all.

 

[Lefty7mmstw]

Some good posting going on here, we all should be listening in. This subscription has a lot to offer. thanks all.

You bet. I've been loading around 20 years and have owned about 40 rifles, and I'm still picking up a new or better way to do something once in a while here on LRH. I've lurked for years, but most of the time forums have those who simply HAVE to flame someone.
I'm not interested in a who's is bigger contest. Getting people on the right track with good loading capabilities and safe, accurate stuff should be our primary concern. That is done pretty well here. gun)gun)gun)gun)gun)gun)gun)