To turn or not (necks)

[Alan Griffith]

I recently purchased 300 new Win 30-06 cases for my '06 Ackley. I culled them via a Sinclair Mic-4 neck wall thickness gage http://www.sinclairintl.com/cgi-bin/category.cgi?category=REMTCG&item=MIC-4&type=store

I was able to cull out 55 cases which had a neck thickness variation of .00075" or less. When reading Glen Zediker's book on reloading he suggests neck turning only the best cases to get them as close to zero runout as possible. I'm dying to turn them but wonder if my chamber's neck to too generous to really make a difference. The case necks are averaging .0013" thick.

My fired case necks are running .341". Sized via my Lee Collet neck die they run .332". A .009" difference.

.308" bullet diameter
.026" neck thickness .013 x 2
.334" total

What do you think of these numbers and whether or not I should turn my necks?

 

[britz]

If you only have a variation of .00075 why whould you waste your time?

 

[Alan Griffith]

Good question! That is one of the things, I'm struggling with. It's Glen Zediker that got me thinking about it. He turns the good stuff, not the less than good stuff.

 

[goodgrouper]

I doubt turning the necks on your particular brass would do much of anything at all advantageous. Glen suggests that he uses that good brass for matches because he figures if it has good consistency in the necks that it will have good consistency throughout the case and will give better results. In other words, he won't try and make a silk purse out of a sow's ear.

However, if your necks have a real thick side, they can be turned and still give good results. I believe in turning if there is more than .001" variation in neck thickness. Your brass is less than that so I wouldn't worry about it. /ubbthreads/images/graemlins/wink.gif

 

[Alan Griffith]

GG,

Again, thanks! So, turn the stuff which runs more than .001".

 

[BountyHunter]

are you using bushing dies?

If not, then you cannot neck turn.

If you have .009, IMO neck turning is a waste of time.

BH

 

[uncleB]

GSSP,
What kind of measuring equipment are you using??? sinclair or anything I have seen or used will barely measure to the 4th decimal point and your necks are .00075" how do you measure 75/100 thousandth. just curious
UB

 

[goodgrouper]

[ QUOTE ]
are you using bushing dies?

If not, then you cannot neck turn.



[/ QUOTE ]


I use standard dies all the time with neck turned brass. While you can't control neck tension without bushings, you can surely turn the high side off of the brass and use regular dies to resize them.

 

[Alan Griffith]

UncleB,

I use the Sinclair Mic-4. It has a .001" dial indicator, but I use by M1A1 eyeball to "read between the lines". Maybe I'm off one decimal place and it's .0075", but that looks wrong to me.

I'm currently using the Lee neck collet die. I can control the tightness of the bullet by changing out the decapping mandrel with different sized mandrels.

I'm thinking before the fat lady sings, I will run a test of turning 10 and leaving 10 alone and shooting a SxS accuracy test. I'll throw in 10 each with thickness variation of .0015, turned and unturned. Total of a 40 round test.

 

[Chawlston]

[ QUOTE ]
are you using bushing dies?

If not, then you cannot neck turn.

If you have .009, IMO neck turning is a waste of time.

BH

[/ QUOTE ]

Wrong answer! Yes you can turn brass for non-bushing dies. I do it all the time. Instead of selecting the correct size bushing for the job, you just select the neck thickness that works the best for you and turn the brass.

You are giving out false information.

James

 

[BountyHunter]

OK you can turn IF you are just cleaning up the necks and taking off the high spots AND your particular sizing die sizes enough of what is left to give a enough bullet grip without the bullet moving in the mag during recoil.

Even then, but you cannot control neck tension without bushings due to work hardening unless you anneal.

However, it still remains with what is cut off in an grossly oversize factory chamber it is extremely doubtful you get any benefit for that work other than to say to you are doing it.

BH

 

[Chawlston]

[ QUOTE ]
OK you can turn IF you are just cleaning up the necks and taking off the high spots AND your particular sizing die sizes enough of what is left to give a enough bullet grip without the bullet moving in the mag during recoil.

Even then, but you cannot control neck tension without bushings due to work hardening unless you anneal.

However, it still remains with what is cut off in an grossly oversize factory chamber it is extremely doubtful you get any benefit for that work other than to say to you are doing it.

BH

[/ QUOTE ]

The benefits of truing up your brass are very similar to truing up an action as it keeps the bullet perfectly aligned with the bore as truing an action will keep the action and barrel properly aligned. Truing up your brass only helps accuracy and I have been doing it on my 06 Ackley for many years with great results (I am still on the original Winchester brass).

Next time you don't think truing up your brass is beneficial, try this experiment. First open your front door and then back off 50 or so yards. Then run to the front door and instead of aiming for the center of the door opening, align your entry so that one of your shoulders will contact the door when you are at full throttle going through the entry way. The results are the same when a bullet is not properly aligned. However the bullet is much faster and the results are more dramatic. The experiment works on ship or submarine doors as well. They just don't move and the projectile will ALWAYS get damaged.

James

 

[kraky]

One of the gun magazines did a recent test on neck turning. I can't remember the issue or the exact amount of testing but in the end I do remember that they could not prove one bit of improvement by neck turning in a factory rifle. As a matter of fact the best group they shot was at the end of the test trying to use up some casings, bullets and powder. They actually shot the best group with a mix of headstamps.
I reload for some friends with custom hunting rifles. It amazes me that on all of them you can take a once fired case that hasn't been resized and slide a bullet into the case mouth and it actually has a tad of friction. To me this means the chamber has been properly made so that the neck is slightly snug (in a matter of speaking) and should help ensure bullet alignment with the bore rather than the usually loose sloppy chambers on factory guns. It would seem to me that by neck turning the brass you would actually negate this positive.
I still believe that 98% of a guns accuracy comes from how it likes the basic's of a load. But I do try to keep my runnout under .003". Some guns seem to shoot anything good. Others seem to respond to different techniques. I guess in the end run you have to decide how much time you want to spend prepping and whether or not it makes much difference on the target.

 

[BountyHunter]

chawlston

Interesting analogy, but your door is a little off center on this I believe.

Think about it. If the chamber neck is .009 or so oversize as most factory necks are, we also know that all factory chambers are oversize compared to min SAAMI match chambers.

Now with an oversize chamber, an oversize neck and now a thinner case neck, just exactly what is centering that bullet in the neck and holding that cartridge in mid air with no chamber and neck contact?

Think it might just be laying on the bottom of the chamber and neck or in your example it is laying at the bottom of the door opening.

Min cleaning up necks for factory chambers is only necessary if your brass is way off center on side of the neck.

If it feels good though, do it, but it will not center the neck and bullet.

BH