7mm brass too short?

MT257

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My buddy came to me with his 7mm as he was having diffuculty chambering some handloads he had. At first I figured the brass was incorrectly sized and needed to be trimmed. I pulled all the bullets and have found the brass range from 2.456" to 2.498". I am confused as to what to do next? Most of the brass falls below the minimum trim to length of 2.49" but I feel the low end is alot short. Would it be best to just start over from the start with all the same brass? I am also confused as to what in the world would cause the bolt so much diffuculty closing if the brass is short, any insight is much appreicated. Thanks.
 

WildBillG

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I would just trim the brass over 2.490 to that length. Although trimming it all to the shortest leng will make it all even. As for the diffacult bolt closer full length resize with a .002 shoulder bump. Do you know how to do this?
 

MT257

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I would just trim the brass over 2.490 to that length. Although trimming it all to the shortest leng will make it all even. As for the diffacult bolt closer full length resize with a .002 shoulder bump. Do you know how to do this?
So are you recommending that I find the shortest piece of brass out of the bunch and then trimming it all that short?
 

zach_destroys

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So are you recommending that I find the shortest piece of brass out of the bunch and then trimming it all that short?
That's what he is saying. After that bump all the shoulders back slightly. That is what is causing the difficult chambering. You can do this with a fl die. The neck isn't too long or overall length too long, but distance from case rim to shoulder.
 

MT257

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So I seated a bullet back to the oal I had measured before pulling. I then took another piece of bras full length sized then seated. I measure to within 0.001” cbto on the two.
 

WildBillG

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I don't think you understand what it means to shoulder bump. I may have my devices mixed up but you will need a case comparator to measure the original case length. Thenwith your FL die touching the shell holder size a case. Now measure it if the shoulder does not move turn the die down 1/8th of a turn and try again. Kepp doing this until the shoulder is bumped back .002. Then set your die there. I am not sure but at that setting it should bump all brass back .002. I may be wrong on this and some one correct me if I am. This is the way a lot of top shooters are now setting up their dies.
 

Tiny Tim

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Jan 26, 2015
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Agree with the shoulder bump of .002. Do you have a comparator and do you have a piece of unfired brass to measure and see if it fits in the chamber? How many times has the brass been fired? Generally, I can fire a case a couple of times before its difficult to chamber. It could be that the handloads he's using are over pressure. Did you weigh the powder you removed? In the end, I believe it simply needs to be FL resized. As far as trim length goes you could trim all to the same length or to minimum and hope the short ones grow, but trimming all to the shortest length will be the most consistent.
 

gbett308

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Feb 23, 2018
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My buddy came to me with his 7mm as he was having diffuculty chambering some handloads he had. At first I figured the brass was incorrectly sized and needed to be trimmed. I pulled all the bullets and have found the brass range from 2.456" to 2.498". I am confused as to what to do next? Most of the brass falls below the minimum trim to length of 2.49" but I feel the low end is alot short. Would it be best to just start over from the start with all the same brass? I am also confused as to what in the world would cause the bolt so much diffuculty closing if the brass is short, any insight is much appreicated. Thanks.
I would resize all of the brass after ensuring it is the correct length. Follow the directions on the dies and make sure they are set up exactly as specified. Check fit after resizing in rifle chamber with resized brass first before reloading.
 

MT257

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Aug 26, 2015
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I would resize all of the brass after ensuring it is the correct length. Follow the directions on the dies and make sure they are set up exactly as specified. Check fit after resizing in rifle chamber with resized brass first before reloading.
This was my initial plan. Start over from the start of everything, but how does one determin in this situation what the correct length is since most of them are shorter than the trim to length?
 

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