To turn or not to turn....

O

Obtunded

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I hauled out some of my precious virgin Lapua 6mm BR Norma brass to prep some cases for tomorrow's KTSA winter league shoot off. I expect CyaN1de and the Frippulator to hand me my arse on a platter, but I wanted to try and mitigate the extent of my humiliation by meticulously prepping some brass.

I grew-out of the idea that tight necks and thinly turned brass were the panacea to accuracy, however i still strongly believe that cleaning up necks is an important step.

Before getting to this step, i use a neck turning expander mandrel that opens the cases just enough to allow the turning mandrel to accept the cases with zero slop.

neckturn3.jpg


I have a photo of 4 pieces of brass from the same batch. The case on the left is a virgin case and clearly shows the patina from the factory annealing job. The two middle cases show that in spit of setting the cutter to remove just under a thou of materal, the case necks are irregular enough in their consistency that the cutter did not touch some of the thinner areas. The case on the right - from the same batch and with the same cutter adjustment - cleaned up completely with no exposed low spots.

I firmly believe that cases that are not concentric will seat the back of bullet off the axis of the bore and this can affect long-distance accuracy.
 
Good luck tomorrow! I tried neck turning, but couldn't see much difference at the target. I am very fussy about the oal of the brass (Lapua, of course), and the neck tension on the bullet. This has proved to be very important to me in LR target shooting.
 
New brass for tomorrow huh?

Platter? I think not....not on my end anyway.

Colleen and I went for breakfast with the Frippulator this morning. He says your going down in a ball of flames though...... LOL

I believe I turned all my 6BR to .013 and am turning my 308 brass for the 260 to .014 Running a virgin case in the Casemaster it is showing .014-.016 on 1 308 Lapua case neck.
 
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If you had the time and/or inclination, I'd love to see you run a test and see if you could substantiate whether neck turning definitively translates into a difference on paper -and if so, how much of one.
 
there may stii be a come for behind in a stock .223
if i can just arrive after scorekeeper and replace lock.. possibitlity of winnin without x - count
 
NewInWestsyde said:
there may stii be a come for behind in a stock .223
if i can just arrive after scorekeeper and replace lock.. possibitlity of winnin without x - count
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Sean,

At the rate I'm pounding back the wine right now, you could be right! I just have to figure out how to line Richard's gonch with nicotine patches without him knowing.
 
To turn or not

It will all depends on the chamber your'e feeding, tight neck, then turning is a must, but on factory or no turn chambers, NOt required provided you have checked the neck thickness of the brass. IE. I use new but old stock Herters brass (Norma) for the 6.5X55, measured it's no more then 0.001 variation, why would I turn this????
Bill
 
In general, I favor neck turned brass and most of my rifles require it. I have come to believe that there are a number of factors which influence the necessity and the efficacy of turning.
If the chamber neck and throat are minimum spec, the rifle will be less tolerant of misalignment in the cartridge. Coversely, a chamber/cartridge combination which posesses greater clearance will be more tolerant. Tolereant to the extent that turning may be of little value.
Cases which are turned so as to be perfectly concentric in the neck may still be screwed up during the sizing operation by a neck sizing die which is too sloppy or a bushing type die in which the bushing has excessive "float" in the die body.
One thing I believe to be hypercritical when necks are turned is bullet seating depth. I am convinced that the bullet must be kept ahead of the neck/shoulder juncture. If not, the donut (which begins to appear after just a couple firings) will affect bullet alignment. Regards, Bill.
 
If I could make a small suggestion. From past non firearms competition I learned a very valuable lesson. Never change anything the day or night before a competition. Use what you've practiced with. Change it after the competition and then practice for the next one.

That lesson cost me a Canadian Nationals title once.
 
Epoxy7 said:
If I could make a small suggestion. From past non firearms competition I learned a very valuable lesson. Never change anything the day or night before a competition. Use what you've practiced with. Change it after the competition and then practice for the next one.

That lesson cost me a Canadian Nationals title once.
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SHhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh!!!!!!!!!! ;)
 
Leeper said:
In general, I favor neck turned brass and most of my rifles require it. I have come to believe that there are a number of factors which influence the necessity and the efficacy of turning.
If the chamber neck and throat are minimum spec, the rifle will be less tolerant of misalignment in the cartridge. Coversely, a chamber/cartridge combination which posesses greater clearance will be more tolerant. Tolereant to the extent that turning may be of little value.
Cases which are turned so as to be perfectly concentric in the neck may still be screwed up during the sizing operation by a neck sizing die which is too sloppy or a bushing type die in which the bushing has excessive "float" in the die body.
One thing I believe to be hypercritical when necks are turned is bullet seating depth. I am convinced that the bullet must be kept ahead of the neck/shoulder juncture. If not, the donut (which begins to appear after just a couple firings) will affect bullet alignment. Regards, Bill.
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Sounds like solid advice.
Do you believe a tight neck/neck turning makes an accuracy difference over a tight spec (with stock Lapua brass) on a 600 yard 6mbr??
 
Bill, would it be then advisable to ream the donut from the body/neck joint, or leave it alone?? It is real noticeable on my 35 Brown/Whelan cases after 2 or 3 firings and the 250 gr. bullets are seated deeper than donut. This is a hunting rifle but ??? Mark
 
Epoxy7 said:
If I could make a small suggestion. From past non firearms competition I learned a very valuable lesson. Never change anything the day or night before a competition. Use what you've practiced with. Change it after the competition and then practice for the next one.

That lesson cost me a Canadian Nationals title once.
Click to expand...

Nothing new here except I was drinking chardonnay instead of rum while reloading. I did find myself loading more flamboyantly though...
 
Obtunded said:
Nothing new here except I was drinking chardonnay instead of rum while reloading. I did find myself loading more flamboyantly though...
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loading...thats what i forgot to do last nite
maybe i got a few boxes of cheap win to bring
or i could bring out the .243 ... it's a 6 mil rifle too
 
X-Fan,
If a chamber/brass combination is truly "tight",which Iconsider to be .001" or less radial clearance, neck turning is probably beneficial if only to eliminate the occasional flyer caused by misalignment. So the short answer is, yes. In a tight necked chamber, neck turned brass is likely to be more accurate by a very small margin. I'm becoming more and more convinced that more clearance (a slightly larger chamber neck) is preferable and will perform better in the real world. Note: I do not consider short range BR to be "Real World"! It's a different game where 1/4 moa is just enough to keep the competitor from putting a bag over his head!
358
I wouldn't worry at all about the Brown-Whelen. In the first place, the donut in this instance is from a different cause than the donut as it appears in a neck turned case.
In a neck turned case, the donut appears as brass moves forward under the pressure of firing and the brass from the end of the turning cut enters the neck.
In an unturned case, the donut which appears is the result of the structural rigidity of the neck/shoulder juncture. This is especially evident in cartridges with very sharp shoulers. The brass is not really thicker than the rest of the neck as it is in the neck-turned case. If the donut is reamed out, you will actually have a thin spot at the base of the neck.
The second point with regards to the Brown-Whelen is this; the accuracy level is not such that the tightness at the bottom of the neck is like to have much effect. In addition, the donut is likely to be concentric with the rest of the neck. This is not the case with the donut which rears it's ugly head with neck-turned brass. Regards, Bill
 
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