Thread: 7mm Rem Mag sizing problems

I sat down tonight to resize my once fired Norma brass with my hornady FL die.
The cases are really tight on the last quarter of the stroke and I’m getting a ring at the bottom of the cases where the die goes to that looks like it’s scraping the brass off the exterior of the cases. Is this a faulty die ?

My Hornady Custom dies do exactly the same to 308 cases - Lapua, Federal, Nosler, PMC.
IMHO - don't worry about it.
BUT - I'm sure other older, more experienced heads will help.

If they chamber ok I wouldn't worry either. That bit can be tight to size, but You do often get a line there after more firings though which is the case thinning, keep an eye on that with a paper clip to feel for it or cut a case open from the batch.(but you will see it on the outside clearly)
I've had some guys say the thinning is a headspace issue. But maybe it's more a loose chamber/tight die situation, as my headspace sizing is much the same as a fired round.

Do they chamber and extract ok? or are there problems there?

I've been using a 7mm neck die and only full size after three reloads. saves working the brass.

I'd try to borrow another die/dies of different brands and see if you get the same out come. This will tell you if your chamber is slightly over size or reloads are a bit hot and you're getting a bit much expansion( could be either) norma brass is a bit soft and may expand a little bit easier than some. I use it and like it. Also make sure your die is set correctly, not pushing the shoulder back more than is needed and sizing more of the case is needed. You could also send some fired cases and your die to a gun smith and get him to modify it to match your chamber but probably cheaper to get another die of another brand if that solves the problem

I am not sure what to say of it… I have reload for 7mm rem mag quiet a bit as i had 2 rifles at the same time for different purposes, i saw many different case signs but i cant make my mind about yours just yet, the photo is a bit blurry when zoomed in, however i will mention here what i am seen.
just above the belt you have a "dark ring" and then a lite "opaque"ring before the brass get back to the "original colour. MHO is the (if the brass has been reloaded only) it was a hot load, or your chamber is "sloppy" or your head space is not set appropriately. If your head space is "wrong" your brass is growing in length and when you resizing it your brass should be feeling harder to be fully inserted in to the dies and because to has been stretched during firing it will show this discolouring lower as the material has thinned… try to measure another brass that has not been fired in your rifle and compare with one of your brass in overall length.
"I" think few of our members here gunsmiths and "professional" re-loaders with a lot more experience will "chip in" with more solid information.

I will reserve my opinion about fire it again or not as "I" don't know exactly what to say about it…

Cheers, i really hope someone come to the "table" with a better info so i can also learn more about things like it.

Mac

Here is a suggestion, depending on when a chamber is formed, the first one off the line will have a chamber diameter of .006" more then the one off the line just before new tooling is installed. This is the SAAMI tolerance of major to minor size. Now sizing dies are designed to take brass down to minimum size so it will fit in all chambers. So major chamber size and minor die size creates alot of working of the brass.

My 7mm Mag brass looks the same, I use RCBS dies. Haven't had any issues just watch them after several firings for case separation.

THANKS for all the reply’s , I’m getting the brass measured tomorrow new fired and sized so I’ll see if that tells me anything. Also I might run a fired case through a mates dies to see if it’s the same. A loose chamber sounds likely but the measuring might answer that.
I’ll post the results.

I don't think its the chamber or the Die. If it chambers all's well like Mooseman says looks like my brass as well. Use a high quality lube like Imperial wax. If it doesn't chamber well that's different.

Compared to an unfired round the shoulder on the resized brass doesn’t seem to be bumped back down enough

Originally Posted by falcon6555

Compared to an unfired round the shoulder on the resized brass doesn’t seem to be bumped back down enoughAttachment 85164

Check overall case lenght of resized brass is in spec. You do not want it tight on the mouth of the neck in the chamber!
It sounds like you jave a largish chamber and when you squeeze that body brass back in it has to go somewhere and it pushes the shoulder forward.Check it is actually tight on the shoulder and if so wind die down an 1/8th of a turn at a time untill the bolt handle just closes with very light pressure.If you cannot get anymore sizeing you may need to grind or machine a touch off of the bottom of the die to let the case enter it further.

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The brass has been trimmed to length and is ok it just won’t physically go any further into due. Shop is looking at it but I suspect you’re right and it’s a largish chamber, will see what they come up with

Originally Posted by veitnamcam

Check overall case lenght of resized brass is in spec. You do not want it tight on the mouth of the neck in the chamber!
It sounds like you jave a largish chamber and when you squeeze that body brass back in it has to go somewhere and it pushes the shoulder forward.Check it is actually tight on the shoulder and if so wind die down an 1/8th of a turn at a time untill the bolt handle just closes with very light pressure.If you cannot get anymore sizeing you may need to grind or machine a touch off of the bottom of the die to let the case enter it further.

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I had this with my AI dies, had 20thou ground off shellholder and was sweet as from then on