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How thin do you shave your case neck? ( Neck Turning)

Posted: Wed May 13, 2009 9:17 am
by kirbymagnum
Before neck turning my case neck thickness is 0.013" and after it is 0.010" it seems like I'm shaving off quite a bit. Is this too much or not enough? What are the consequences of shaving to much off?

Re: How thin do you shave your case neck? ( Neck Turning)

Posted: Wed May 13, 2009 10:32 am
by Rick in Oregon
kirby: You may have already taken off too much if it's for a factory chamber. You really only want to "uniform" the necks, make them all the same with the minimum of material removal, only taking off the high spots and leave at least 50% untouched. My Hornet necks are .010" thick, the 222 family of case necks are usually at least .012"+ in most chambers.

If too much material is removed, there may not be enough brass left to properly spring-back after firing and the case won't hold a bullet, even after sizing. Then you'll need bushing dies if that is indeed the case in order to use those cases again. Been there. :?

Re: How thin do you shave your case neck? ( Neck Turning)

Posted: Wed May 13, 2009 10:36 am
by Wrangler John
Depends. Why are you turning necks in the first place?

I have to turn necks for custom precision chambered barrels with tight dimensioned necks designed to be turned, or for the 6mm PPC chambered for the .262" neck. Generally, neck turning is not necessary on today's brass - yes, heresy according to some, but after measuring Remington, Winchester, Hornady, Nosler, and Lapua brass I concluded that they are all fine right out of the box or bag.

In standard chambered barrels that allow sufficient neck expansion to release the bullet, turning is not necessary and a waste of time. Problem with thinning too much is one of bullet pull, not enough and accuracy can suffer, bullets can be pushed into the case (or fall out of it). I have done experiments with turned necks and never found any better performance in chambers cut with SAAMI dimensioned reamers.

If you want to just clean up a neck, removing the high spots, just do that. I wouldn't go thinner than .010" in any event.

Re: How thin do you shave your case neck? ( Neck Turning)

Posted: Wed May 13, 2009 11:19 am
by kirbymagnum
I have a pacnor barrel, thanks for the quick responses so I don't have to throw out many cases. I was neck turning just to clean up the necks and to take out the high spots.

Re: How thin do you shave your case neck? ( Neck Turning)

Posted: Wed May 13, 2009 9:29 pm
by surfclod
I just began neck turning over the winter and after a lot of searches decided that the 0.012" figure for neck thickness came up enough that it was a good number to use. Most of my brass averaged about that anyways so after a lot of trial and error I have my Forster case trimmer tool set up to turn necks to that measurement. I have about 200 left to do then I will have nearly 1000 brass all prepped and ready to go, most get about 25% of the neck cleaned up, some have up to 75% of the neck area shiney by the time I am done. I just run them all through the tool and if no brass is removed I measure the case sometimes I get one that measures below 0.011" that I set aside but most end up right around the 0.012" mark.

(should also mention this is for a factory barrel)

My current brass prep is thus; annealed, trimmed, flash hole deburred, primer pocket uniformed, and neck turned. Then check loaded cases for concentricity. My accuracy has increased significntly, from 5/8-3/4 MOA before to below 1/2 MOA now with a lot dipping to the 0.3"s (and even my first in the 0.2" territory at .268" :) ) Of course the real test will be multiple 5 shot groups but that has to wait till fall when paper is my commonest target, now Skippy get all the attention.

Re: How thin do you shave your case neck? ( Neck Turning)

Posted: Sat May 16, 2009 6:29 pm
by Wrangler John
In the June 2009 issue of Handloader Charles E. Petty wrote in an article ".223 Wrap-Up" about his experience with a Cooper Phoenix rifle and going through all the folderol of weighing brass, checking neck thickness, primer pocket depth, then turning necks, doing the primer uniformer and deburring thing, and all the rest. Nothing improved group size. When he annealed the cases, groups got worse. Neck sizing didn't help. Then he shot five groups with one shot from of each of five brands of brass - groups were right in the middle of the range between largest and smallest (we are told never to mix brass by lots, let alone manufacturer). Case weight consistency didn't matter, neck thickness didn't matter, loads with low standard of deviation were seldom the most accurate, and all our commonly accepted rituals were, as they say on Mythbuster's - Busted. Best accuracy was with new unfired Remington cases on their first firing - they beat Winchester, Nosler, Norma and Lapua brass. Remington 7 1/2 BR primers produced the smallest groups (that I knew from experience) and seating .020" off the lands also was the most accurate (with my .204 Ruger seating to factory OAL produced the best accuracy.

This is pretty much my experience too, although I am reluctant to admit it. Man, I thought I was really doing something with all those tools, gauges, micrometers and that trusty scale. Now I can relax and enjoy running the stuff through the progressive press and cranking them out. :lol: But then I'm a :doh: really lazy dunce with hands that cramp from repetitive motions.

Re: How thin do you shave your case neck? ( Neck Turning)

Posted: Fri May 22, 2009 6:52 am
by skb2706
In my opinion its not possible to know how much to take off without knowing what your chamber measures. Otherwise its just a guess. In my custom cut chambvers I like .001 to .0015 bullet release. My 6mm chamber measures .264", loaded rounds with necks turned measure right at .2625-.263".

Re: How thin do you shave your case neck? ( Neck Turning)

Posted: Sat Jun 06, 2009 6:10 am
by bigun
0.012" for me any more would just be to much .224 neck die used