Home Forums Reloading Big Game Rifles Case Separation

Long story - short, had my Remington ADL 7mm Mag rebarrelled as the old one was shot out. Since the new barrel was fitted I have been having continuing problems trying to get it to shoot and finally have sorted a load that flies at 3200, groups 4" @ 300 - excellent, minute of deer, all I ever ask of a hunting rifle. Had a session at the range today, shot off various loads to arrive at the one we want. Now I'm back home in at the reloading bench and 2/3 of the cases have separated or showing signs of separating! LRP brass, loaded 2-3 times, 4 at max - what am I doing wrong? Tried similar loads in my Husky with no indication of separation.
Any help would be welcomed, Cheers, Al

Does one full length resize, and was that brass run through your previous rifle?

Up until today I hadnt changed anything from what was set up for the old barrel. RP brass, loaded a max of 4 times each, but for this exercise I used once fired cases. After posting I went back to the bench and checked my dies to ensure they were headspacing on the shoulder, not the belt, and they were. I then tried the same sized cases in my Husky and could hardly close the bolt! Had to turn the die down over 1 1/2 turns just to get an empty case to chamber freely in the Husky.
Also since I have had the barrel changed I have had maybe 10-12 cartridges fail to fire - dent the primer but fail to go off. Doesnt happen in the Husky, never happened before the barrel was changed.
I'm seriously starting to think we have a head space problem!

Sounds like your Remington has a longer chamber. You need to try to adjust your sizeing die out to compensate. The fact that you had to adjust the die down 1 1/2 turns to chamber in the Husky pretty much confirms this.If you keep sizeing the cases to fit the Husky when you fire them in your new Remington barrel they will stretch and separate. I would buy another size die and set one up for each chamber. Or you could keep adjusting the one die for each chamber. Not hard to create a headspace issue by oversizeing.

Here's a better mouse trap for multiple, like chambered guns:


http://goo.gl/DO5z2

Maybe start with new brass & run it over a thirty caliber expanding ball. Then neck size short in your 7mm die leaving a false shoulder to force the base against the bolt face. A different sizing die set up for this rifle would be a good idea also.

aalf,

Thats pretty slick. I forgot about Reddings competition shell holders also.

Yep, the Redding shell holders work great. It's a lot more secure feeling to bottom out on the sizing die than to wonder how much spring was induced into the press. Saves on multiple sizing dies in the same caliber..

Thanks guys, slept on it and did some thinking, out to the bench this morning and put a row of brass from the Husky and a row of brass from the Remington on the window ledge in the light just to make a "by eye" comparison. I can immediately tell the difference without even looking too close - the Husky brass is slightly shorter in the shoulder, they all look neat and straight where they need to be. The Remington brass has a curved section where the shoulder turns up to the neck and they dont look as neat or crisp [for want of a better description] as the Husky brass.
I had thought of some sort of shim or stop for the die - the shims from Sinclair look just the part. And I had contemplated another die for the Remington.
Problem is that I now need to keep my brass separate, so it looks like the easiest way for that is to buy some new brass from a different manufacturer and work on the head stamps.
But it still begs the question - should a newly fitted barrel have such a long chamber? Should I send it back to the smith [again] and have the barrel set back?
Cheers, Al

start fresh with new brass for the remington, make your decision from those new cases. Neck size the cases if you can.

To designate brass for different rifles, dip the base of the brass in Insta-blue. The base of the case will be turned permanently black for easy identification.

If you are familiar with Ogive gages, a 33 or 35 caliber ogive gage will fit over the neck and you will be able to measure just how much the shoulder is being blown forward on the new brass alomg with how much you are pushing it back when sizing.

good luck

I would tell the smith what is going on. I wouldn't want my new chamber to be that much larger than a factory chamber, even if the Husky is on the small side. That's too much variation for me. If anything, I want my custom chamber to be tighter then factory specs, with allowance for a quality job by Husq. I would want my smith to set it back and so it right.

Gunsmith would have to get a different reamer with the shoulder repositioned. The belt on the 7 Rem mag is what determines the headspace.

As for setting up the FL die for each rifle, find the proper location for resizing and use feeler gauges to determine the gap between the shell holder and the die. Put notes in die box as to which feeler gauge for each rifle.

Exactly.

You paid good money for him to do it right, send it back.

Took the rifle back to the gunsmith today, along with the problem cases and a selection of other cases. Put the "Go", "No Go" gauges through the rifle and also put a selection of cases across the mic'. The rifle was had been headspaced to about halfway between the 2 guages, standard rechambering practice I am told to allow for a variety of different factory loads. We also checked it against my Husky and the Husky reloads. I also went over how I set my dies just to ensure that I had got it right.
He then told me that he could set the barrel back a few thou if I wanted, and headspace it as close to the Husky as possible so I could use the same die setting for both rifles. Then he asked how long I was in town and told me to come back in 2 hours and the job would be all done. I picked up the rifle and am now waiting for a day to get it to the range and check it out. The barrel was set back 4-5 thou.
He also told me that most case separation is as a result of the first shot - may not occur at the time, but because of the weakness created by firing the cartridge in a chamber approaching max headspace [or more], case seaparation will usually occur soon after. The cases I used were a batch of once fired RP cases I had bought to work up a load with the new barrel. They were not first fired in this chamber. so maybe I started off with a bad batch of brass.
I have since gone over all my 7mm Mag cases with a probe to check for weakening and binned about 50 of them. The rest have no signs at all, so I will load up some old Norma cases and see if we cant get this rifle to shoot [finally]
cheers, Al