Resizing and trimming...

Pinecricker

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Dec 23, 2014
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North Idaho
can any one suggest an intuative way for correctly setting dies to do partial resizing, and for determining the correct length to trim cases? I trimmed to book spec, but an still getting a tight fit. No way to tell if its not resized enough, or not trimmed enough, if that makes sense. Its a rifle with a custom cut chamber with a short throat, so the book specs don't always match. One article I read mentioned a special gauge could be necessary.

Any insights are much appreciated. Thanks!
 

WapitiBob

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Trimmed to book length won't prevent chambering but maybe 1 in 1000.

I use a bump gage to measure a once fired case, measuring case head to shoulder, making sure there's no primer in the brass.
For sizing, I light a candle, take a once fired case and roll the shoulder thru the flame to "smoke" that shoulder. I set my sizer to be several turns up off the shell holder and run the sizer down the case. I adjust the sizer down till it just touches the smoke on the shoulder. I then remeasure the newly bumped case. I should be bumping the shoulder only a cpl thou.

Usually, screwing the sizer down till it hits hard on the shell holder will bump the shoulder back about .010 which is way too much.
 

Rooster52

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Feb 18, 2014
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I always full length size all my brass. I have tried neck sizing and found some tight bolt closings ,so now I full length size and no more problems.If you are trimming to book specs,I dought that your trim length is giving you any problem.I myself have never had that problem.
 

mtmuley

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montana
Pinedricker, with the custom chamber, you may need to trim and uniform the outside of the case neck. mtmuley
 

cowboy

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Jul 26, 2009
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Mt/Id/SD
My first quess on your situation is you are not getting enough shoulder bump on your resizing, trimming OAL a couple thousandths is usually not the problem.

It would help to know a couple things before just keyboard guessing.
- what cal. are you reloading - is it a belted mag.?
- what dies are you using and what is your die set up procedure?
- is your problem on new brass, once fired or multiple fired brass?
- what bullets are you reloading and how close to the lands are you seating them?
- last but not lease is, how hot of loads are you pushing these bullets?
- are you using brass only shot out of this rifle and is your brass all the same manf, lot number etc?

What is your definition of "still getting a tight fit"? A little resistance in closing a bolt is exactly what a couple of my custom rifle chambers require to shoot to their max potential. If I bump the shoulder more than that to get "no resistance" on my reloads my accuracy on paper shows it.
 
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