Neck turning question

[transdude]

Hi all,

This is my first post here, sorry if it is long.

Here's my question- when turning necks how much is enough?

The gun I'm shooting is a Remington 40X in 6 br. that I want to use for varmint hunting.

The load is a 70 grain moly Blitzking over 30.5 grains of H322 with a Fed match primer in a Lapua case,bullet is seated about .010 from the lands).

I'm new to turning necks.
The chamber is stamped ".266 neck" and what I'm doing is turning the necks to .011 which is giving me a finished round that is exactly .265

Is .001 enough space for proper bullet release? I've already prepped more cases than I care to talk about, but if necessary, I can shave the necks a bit more- I'm using a Gracey and it goes kind of quickly.

By the way the gun / load shoots like crazy- I haven't shot it too much yet, but so far at 300 yards it has grouped 5 shots at around .748,.527 if I don't count the flyer).

Any thoughts / advise?

Thanks.
-John

 

[wnroscoe]

Sounds like you got it going your way. My 6br has a .269" neck and my loaded rounds measure .268", the 6PPC crowd usually has .262" necks and loaded rounds at .261", you'll be fine.

 

[transdude]

Thanks for the help. I'm glad that I don't need to turn 500+ cases for the second time.

CatShooter, The load is a 70 grain moly Blitzking over 30.5 grains of H322 with a Fed match primer in a Lapua case,bullet is seated about .010 from the lands).

Thanks again.
-John

 

[Klong]

I turn mine just enough to allow a bullet to be hand seated in a fired case.

 

[peter prunty]

Hi all,

This is my first post here, sorry if it is long.

Here's my question- when turning necks how much is enough?

The gun I'm shooting is a Remington 40X in 6 br. that I want to use for varmint hunting.

The load is a 70 grain moly Blitzking over 30.5 grains of H322 with a Fed match primer in a Lapua case,bullet is seated about .010 from the lands).

I'm new to turning necks.
The chamber is stamped ".266 neck" and what I'm doing is turning the necks to .011 which is giving me a finished round that is exactly .265

Is .001 enough space for proper bullet release? I've already prepped more cases than I care to talk about, but if necessary, I can shave the necks a bit more- I'm using a Gracey and it goes kind of quickly.

By the way the gun / load shoots like crazy- I haven't shot it too much yet, but so far at 300 yards it has grouped 5 shots at around .748,.527 if I don't count the flyer).

Any thoughts / advise?

Thanks.
-John

 

[peter prunty]

Can anyone tell me how to post a question? I am a new member and have limited computer skills.my e-mail is peterprunty@att.net

 

[ireload2]

At the top right end of the bar there is a blue button that says "Post a New Thread" Pick it.

http://forum.accurateshooter.com/forums/reloading-forum-all-calibers.2/create-thread

Can anyone tell me how to post a question? I am a new member and have limited computer skills.my e-mail is peterprunty@att.net

 

[zx10mike]

one thing to bear in mind when neck turning and perhaps you guys can share your thoughts on this but with only 1 tho clearance i find despite turning into the shoulder and doing a second turn ,brass flow happens and can soon narrow that gap ? as a result i have done a third skim but only as far down as the bushing sizes so not to go to thin near the shoulder.thoughts anyone?

 

[John Russell]

one thing to bear in mind when neck turning and perhaps you guys can share your thoughts on this but with only 1 tho clearance i find despite turning into the shoulder and doing a second turn ,brass flow happens and can soon narrow that gap ? as a result i have done a third skim but only as far down as the bushing sizes so not to go to thin near the shoulder.thoughts anyone?

My 6mmBR has a 0.262" neck - my first time around, I turned cases so my loaded diameter was 0.261"... the rifle shot well (sometimes) but it constantly needed cleaning and it was a real spoiled, finicky princess.
So much so, that I shot it less and less, and it finely would up sitting in the back of the safe, collecting dust.

Then I saw a video by Jack Nearey (Hall of Fame, bench rest shooter)... where he had the same problems. He suggested cutting necks to leave a total of 0.0025" to 0.003" clearance... it solved his problems.

So I turned another 0.001" off of my necks, and the rifle came alive... easy peasy to live with and not at all finicky - a joy to shoot and live with.

 

[dmoran]

^^^^^ +1
I to have seen no accuracy gains to "tight necks" and prefer +.003" clearance.
And in my opinion, 1-thou is a risky clearance without meticulosity to detail to many effective aspects.
Donovan

 

[BoydAllen]

Among those whose goal is extreme accuracy, there has tended to be an assumption that smaller clearances are always better. Experimentation has determined that this is often not the case. There is an optimal clearance that may be less than that built into production rifles, but going smaller than that can have negative consequences. If you look at what top short and long range benchrest shooters are doing, you will see that clearances are chosen on a case by case basis. For instance, while it may work well to limit shoulder bump to .001 under the largest shoulder (really datum line) to head dimension that brass can attain in a particular chamber, neck clearance that is up to three times that (for 6mm) may be better in that location. Another example is the size of the back of the back of the chamber relative to the size of unfired brass. Get it too close, and you will have clicking problems with warm to hot loads, that may be your most accurate, that could have been avoided with a slightly larger dimension in that area.

Somewhere in this thread was a question about the cause of brass "flow" into necks. This is caused by the degree to which the body of the case is reduced in diameter during sizing, and the amount that shoulders are bumped back.

Back in the day I had a .220 Swift that I loaded for with a RCBS one piece FL die that sized the body of fired cases quite a lot. As a result, even with the shoulder bump set properly, case growth was excessive. In those days, RCBS offered the service of lapping out the body of a die for minimal resizing, so I took advantage of that service and sent them my die. After it had been lapped out, the amount that my fired cases were reduced in body diameter was significantly reduced, as was case growth produced by FL sizing.

Currently I have a FL bushing die that is a very good fit for brass from chambers cut by my 6PPC chamber reamer. If I keep a close eye on the die setting so that I do not bump shoulders too much, case growth is very small.

When you reduce the body diameter of a longer case, it adds up to more brass shoved out the end then with a shorter or smaller diameter case, so this is another contributing factor.

I find that most reloaders have not measured case diameters before and after sizing above the head (where the end of the chamber and die sizing are) and at the shoulder. I think that their understanding of what is going on would be improved if they did.

 

[DRNewcomb]

....And in my opinion, 1-thou is a risky clearance without meticulasism to detail to many effective aspects.

I think the correct word is "meticulosity."

 

[dmoran]

I think the correct word is "meticulosity."

That's better... lol.... edited above, Thanks

 

[joshb]

I turn to 3K clearance.