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Headspace gauge/resizing die question

 
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  #22  
Old 02-13-2011, 07:54 PM
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Re: Headspace gauge/resizing die question

"You are right but I tend to follow the directions From the people that designed the equipment first."

"Die directions" are not an end all. They allow noobs who don't have a clue what they're doing to make ammo that will chamber and go BOOM, but no more than that.

Given the normal slight variations in chambers, cases, presses, dies and shell holders there is no way a simplistic set of instructions can possibly explain in simple "1-2-3" steps how to properly set up a FL sizer. Doing it "right , ie, by the factory directions, will almost always make the cases too small so they WILL stretch each time they are fired.

Most bottle neck cartridges have maximum-to-minimum shoulder location variation - headspace - of about 6 thou. A "small" 1/4 turn die adjustment potentially moves case shoulders almost 18 thou, fully equal to three times the permited headspace range. Even a 1/16th turn moves the die 4.5 thou and that's more than enough change to materially affect chambering.



"In my opinion all new comers need no less than 3 books that are well read and allways back up any info from the internet with a book."

The ONLY reason a noob with a single good loading manual needs another one is for working with new cartridges or new powders and that's not a common need. Noobs with multipule manuals are NOT helped with the extras, they WILL instead be confused and lose confidence because the books always give conflicting loading data. I've been reloading since '65 and now have about 30 manuals, added less than one per year. But I only had ONE (Lyman) manual for the first five years and that didn't handicap me a bit. When I finally got my second manual I had enough experience I could intelligently deal with the conflicts.


"Head space guages will not tell you the size of your chamber after all all guns are not the same."

That's certainly true. But everyone should understand that "headspace" only applies to the chamber, not the case. We need to size our cases to match the headspace and that's fairly easy to do. The various case shoulder gages (Sinclair, Hornady, RCBS, Innovative Technoligies) allow us to match our resized cases to match the fired case shoulder location, which will be a few thou less than the actual headspace/chamber size. Actually, real headspace means nothing to a competent handloader who knows how to properly adjust his FL sizer. (And that's NOT according to the directions!)


"And also incipient separations can be caused by more than how you set your die take pressure for one."

Incipient head seperations aren't real seperations. The case stretch lines are simply the preliminary (incipient) signs of an impending real seperation. But, no matter the chamber pressure, if a case actually fits the chamber properly there will be very little stretch with each firing and the neck or body will normally split before a head seperation occurs.
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  #23  
Old 02-14-2011, 06:21 PM
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Re: Headspace gauge/resizing die question

Thanks for all the info on this subject. I know that I am going to reset all of my resizing dies.

Jason
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  #24  
Old 02-15-2011, 03:17 PM
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Re: Headspace gauge/resizing die question

Again thanks for all the information that everyone has given in the subject of headspace and setting up resizing dies. I adjusted my resizing die for my .243 win today. Fired cases had resistence and when I bump them back .0002, the bolt closed easier. Now I'm going to have to readjust for my .223 and .30-06.

Jason
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  #25  
Old 02-15-2011, 05:06 PM
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Re: Headspace gauge/resizing die question

"... .0002, ..."

You sure? That's only .2 thousants of an inch! Not many loads would ever notice such a tiny difference!
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  #26  
Old 02-15-2011, 05:46 PM
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Re: Headspace gauge/resizing die question

Sorry!! Added too many zreo's. It should be .002 inches.

Jason
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  #27  
Old 02-16-2011, 08:28 AM
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Re: Headspace gauge/resizing die question

The problem lies in the SAAMI specs which give min and max dimensions for chambers and cartridges and reloaders not understanding what is going on.

Cartridges are always built to go in the minimum chamber and chambers are routinely set to maximum specs to ensure that all cartridges fit.

Most of the die manufacturers also build their dies for the min specs to size everything where it will fit in any chamber again. No concern is given to long case life.

You have .006 normally between a GO and NO GO guage for the caliber and then you have another .009-.010 for the normal FIELD gauge.

It is possible to have up to .015 variance between the chamber shoulder (that is also assuming it was in spec to begin with) and the cartridge shoulder for the virgin cartridge or reloaded cartridge IF you screw the die to the shellholder. That is a bottleneck cartridge and belted cases can have even more variances.

The FL dies are set to squeeze the base back to the minimum normally also and that is the arguement that the NS only advocates jump on.

Problem is that the NS method still requires either to throw the case away after 4-5 reloadings or resize it way back down and work the brass and that leaves brass that varies in body dimensions. Got to resize all brass with the same number of firings and assume that they all grow the same. That rarely happens so uniformity is in reality out the door.

Expander balls tend to drag on the necks lengthening cases and introducing runout where it may not have existed.

IMO two changes by the reloader that easily fix both issues.

1. Get rid of the expanders balls, go to a straight decapper pin in the FL die. All die manufacturers sell them. Buy an expanding mandrel to fit the necks to take out any dents if you need them.

2. Try several dies to get the best fit body (email the mftrs to get their specs for the body) or take $40-50 and have JLC Precision hone your dies or make a custom FL bushing die for ($100) to fit your chamber to give you the .001 body size that along with the .001 shoulder bump gives you a 100% reliable case that will not have case head separation and long life.

BH
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  #28  
Old 02-16-2011, 08:59 AM
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Re: Headspace gauge/resizing die question

Yet another good explanation.
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