How picky to get with new brass sorting

[tlk]

I got a new box of Lapua brass. Here is the breakdown on neck wall thickness dims only:

<0.001 (measured less than 0.015 and more than 0.014) - 33

0.001 (measured 0.015 - 0.014) - 22

>0.001 - 0.002 - 43

>0.002 - 2

So the question: I have separated out those that are less than 0.001 neck wall variance from those that are right at 0.001, but is there really any difference between the two? I will be using them for hunting and steel, 600 - 900 yards. No benchrest stuff, but would like to squeeze out everything I can from my setup.

Other question: would even be worth turning the neck on that first group? I usually turn my Lapua brass down to 0.014, but with that group, I dunno if my efforts would actually hurt more than help. Any experience/advice about this would be greatly appreciated.


Thanks.

 

[Mikecr]

What cartridge?
How will you be sizing the cases?

 

[tlk]

30-06. I will be using a lee for the neck and a redding die to bump the shoulder.

 

[Boss Hoss]

With a factory chamber you will not gain very much by turning.

 

[Mikecr]

I'm picky in this area because I can't stand loaded cartridge runout. Just declaring that up front..
For you to measure, means you care about it, and your numbers look pretty typical to me.
For a very long and poorly designed case such as 30-06, runout from thickness variance grows seriously with each body cycle (firing/sizing). Trying to control runout here will only be a losing battle. And neck turning won't help at all.

I would use the 45 pieces exceeding 1thou variance, for brass prep setups only. Things like checks for trimmer, turner, uniforming, pilot deburring, chamfering, annealing, necksizing/tension, etc. Toss em in the trash after use, or immediately.

Keep and use the 1thou & under.
If you need more brass, buy twice as much more.
That's me though.

 

[tlk]

Mike, not wanting to be dense, but: are you saying that I shouldn't turn the good cases in order to make them all consistent?


Min saami chamber, if it makes any difference.

 

[Mikecr]

I was suggesting that turning those >1thou wouldn't help with runout.
Within a few reloads it'll be right back.

 

[davewilson]

how much clearance do you have with a loaded round? my thoughts are it won't make a bit of difference. try keeping them separate and see how the accuracy compares between the 3 groups. untouched < .001, turned necks, and untouched > .002. i did this a couple years ago and couldn't tell any difference. this is what BH was eluding to, it takes a VERY accurate gun to appreciate necks with the same wall thickness.

P.S. if you're going to throw that > .002 stuff away, i'll pay the shipping to take it off your hands.

 

[royinidaho]

My opinion/experience is that the larger the caliber the less difference neck turning makes.

For 222 bench rest I was a neck turning fanatic which carried over to the 270 Win hunting rifle shot in hunter class competition.

With the 270 Win, to get all necks uniform I neck turned to make all cases in the batch the same. Trimmed 'em all to the dimensions of the thinnest neck'd case. Got lots of chips. It seemed really fun, at the time.

I then got lazy and turned leaving some unturned portions of the neck.

I then got either lazier or smarter and didn't turn at all. Only sorted by weight.

Of the 3 versions I noticed no improvement or degradation of group size.

With the 270 AM I don't turn at all nor sort by case weight. Things are hunky dory.

I happen to have a 6mm cal chamber on a rifle that is cut tighter so that case must be turned. Neck for those loads will be turned.

 

[Trickymissfit]

I got a new box of Lapua brass. Here is the breakdown on neck wall thickness dims only:

<0.001 (measured less than 0.015 and more than 0.014) - 33

0.001 (measured 0.015 - 0.014) - 22

>0.001 - 0.002 - 43

>0.002 - 2

So the question: I have separated out those that are less than 0.001 neck wall variance from those that are right at 0.001, but is there really any difference between the two? I will be using them for hunting and steel, 600 - 900 yards. No benchrest stuff, but would like to squeeze out everything I can from my setup.

Other question: would even be worth turning the neck on that first group? I usually turn my Lapua brass down to 0.014, but with that group, I dunno if my efforts would actually hurt more than help. Any experience/advice about this would be greatly appreciated.


Thanks.

I'm sure there will be two dozen ideas here, but here's what I do:
* run all the cases thru a full length sizer
** I will then check the cases for runout in the necks, and measure several to
see if the neck walls are uniform
* measure the overall length of each case in the lot, and then trim them all to the same exact length
* deburr and ream the primer pockets if needed
* weigh the cases, and sort them by weight
* take the largest lot by weight and measure the O.D.'s (the I.D. should be to size)
** then do the samething with the others
* if the O.D.'s fit in the window I plan on using; then all is well. I will then shave the necks on cases I plan on using in my smaller calibers (.22 and 6mm)
* I then weigh them all again

Everybody has an opinion on what's too much varience. In my bigger calibers I usually will work with +/- 2.5 grains per lot. Smaller stuff is about 1.5 grains per lot. In something like a 30-06 factory chamber I will often work with a +/- .001" on the O.D. as there's usually plenty of clearence in the neck. My small stuff will run in .0005" (O.D.) lots, with a set number as max for the O.D. and I.D.

I know a couple guys that actually weight the amount of water a case will hold, but I don't have a need to be that precise. Another bunch I know swear that you have to load a round and fire it in each case before you ever start the above, but once again I don't own a rifle that good to even think about it anymore.

Now back to the question what's good and not so good. If your using a threaded die to seat with, and always do a full length resize after firing; I'd not worry too much. But if you plan on using a bushing die I'd shave the necks to where they are all the same on the O.D., and toss out the bottom two cases in the group
gary

 

[Gene]

I no longer turn necks on hunting brass, just ain't worth it. And, most Lapua brass is pretty uniform. A few suggestions: Measure the necks after they have been fireformed once or twice. Don't worry about the new brass measurements. Also, when you do measure, take it to ten thousandths, i.e. .0001". I agree, the need for consistent necks diminishes with the larger calibers. Bottom line, you do not need to turn these necks.

 

[Mikecr]

There you go tlk; both extremes and the truly misguiding between..
It'll go the same with bullet checks, runout checks, sizing issues, range performance, load development, etc. You can consider up front the efforts you're willing to expend towards your best, or your good enough.

If easy is your theme, a general consensus, or canned advice, is easy enough to follow.
But when challenged with results less than stellar, and nothing's making sense, every shortcut becomes a ghost in the closet.
Too much chaos to decipher then..

On the flipside, you might waste efforts making everything as good as you can, and still end up challenged by your gun. Of course this will be, but it's NEVER your ammo. You know, because you didn't take shortcuts. So now you can cross any notion there right off the list.
Far less chaos to decipher then.

IT'S RISK EITHER WAY

 

[Trickymissfit]

I would be much more worried about the neck I.D.'s than the neck O.D.'s. Also just how big is the neck in the chamber itself. If you got .005" clearence, then your wasting your time
gary

 

[Mikecr]

Not following anything you've been suggesting Gary...
Who measures neck IDs?
OD - Thickness = ID
Thickness + bullet dia = OD
You don't measure thickness by FL sizing and then rolling cases on a runout gauge, or reading unseated ODs. You measure it with a ball mic.

Also, there is more to runout than produced by necks, or seating. The entire case contributes, and a 30-06 is alot of case. Thickness variance measured at the necks carries full length of a case. And with each cycle runout grows because of it. On each firing, a high runout case expands with bias rather than centered, which may or may not be noticed in your groups. I suspect not for most.

Gene, thickness is thickness, provided the necks are anywhere near size for seating. It's variance doesn't change with fireforming either. tlk's measurements are sound as Lapua is no more uniform in this regard than any other cartridge brass, and out of the box it's ready to load(no sizing neeed).