I've just finished weight separation on 254 Winchester .308 cases.

26 (10,24%) 0.8 grs tolerance (165-165.8 grs),
178 (70.1%) 1.4 grs tolerance (166-167.4),
43 (16.9%) 0.7 grs tolerance (167.6-168.3).

Only 7 cases need to be discarded.

I tend to split the 178 cases into two batches which will bring them to the 0.7 grs tolerance, too.

Is this an acceptable spread for precision loads ?

Tx for your input.

[This message has been edited by waitaminit (edited 11-26-2001).]

I'd need a few answers to questions before I could answer you question. This is the way I do it. If the cases are virgin cases, Clean, trim the cases to the shortest case. Weigh the cases and select all cases that are within one grain of each other. Recut the primer pockets. Sinclair make the best uniformer I know of. Deburr the inside flash hole, again, Sinclair makes the best. RCBS is also pretty good. Use an old fire formed case to adjust your sizing die and to adjust the length of the neck turning cut. Then turn the necks to a uniform thickness. Then I decide how many cases I need, and weigh all the cases again. I will determine a weight and a tolerance such as 185.0 grains plus or minus three tenths. I will keep all that meet this tolerance and those over the number I want will be replacements for lost cases. Hope that this helps.

I'd say you've done just fine unless you have some sort of match grade super rifle.
If you're going hunting or just plain paper punching there will be other factors that will affect your accuracy far more than the weights you've broke em down into.
I used to get so crazy I even weighed bullets. It didn't make a difference in any of my hunting rifles.

Case volume is more of a factor than case weight.

A lot of work is necessary to get a set of relyable cases: primer pocket and flash hole preparation, segregation to weight and wall thickness incl. neck turning. Fortunately, these steps have to be done only once.

As I shoot my R700 mostly on 100 m, I should not be concerned too much, but I want to have a batch out of the 250 I can rely on at a 1.000 m distance as well (I am an optimist: we have only one 1.000 m range in Germany which they want to close to the public).

I understand that BigBob finds a 0.3 grs spread adequate. Sinclair/Gravatt say 1.5% of case weight (here: 2.5 grs)is the maximum.

Next I will check wall thickness where I want to use a neck turner which is very little in contact with the wall. This gives me an visual impression on thickness variations. Where I find differences of more than 0.0015" (Sinclair/Gravatt), I consider these cases of minor quality as one can expect that not only the neck but the whole body will be of varying wall thickness.
And this, to my understanding, is a major factor concerning accuracy:
on firing, the case will expand asymmetrically thus bringing the axis of the cartridge out of alignment with the center of the bore, this will deform the bullet when entering the throat and accuracy is gone.

It is the first time that I want to go so far in case preparation. Without these steps, I had some good results, but mostly mixed with some unexplainable hits far off.
I want to find out whether this additional work is worth the effort.
I think yes, as I believe that consistency is the only way to accuracy.