Thread: 7mm Rem Mag sizing problems

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

Thats something to check, have inadventantly used a RCBS shell holder with hornady dies a few years ago and wondered why it wasn't sizing properly.

UPDATE
Got the dies and cases back from H&F today and it looks like my old Lee case lube was causing the problem. I am now using hornady lube on a case lube tray and it is now sizing all the way down the case and apart from 3 out if 90 they are all chambering easily .
Case solved and thanks for all the info. The lee lube cane with my original press about 9 years ago and worked fine on my old 6.5 but was no good with the 7mm.

UPDATE
Got the dies and cases back from H&F today and it looks like my old Lee case lube was causing the problem. I am now using hornady lube on a case lube tray and it is now sizing all the way down the case and apart from 3 out if 90 they are all chambering easily .
Case solved and thanks for all the info. The lee lube cane with my original press about 9 years ago and worked fine on my old 6.5 but was no good with the 7mm.