Weighing and sorting .308 brass

[waco]

I have around 500 once fired 1974 LC .308 cases. I want your opinion on what you think is an acceptable +/- weight per case when sorting out your brass after all the prep work is done. I've never really sorted by weight so I'm not sure what is acceptable. +/- 1 grain? 3 grains?

What do you guys think for your .308 brass?

Waco

[Tatume]

Weigh a sample (more is better, 100 should suffice), and calculate the mean (average) and standard deviation. Add twice the s.d. to the mean, and subtract twice the s.d. from the mean. That will give you the range of values that encompasses 95% of your cases. Keep every case that falls within the range, and discard the others. It is likely that you will end up keeping all or almost all of your cases.

[Bullshop Junior]

I don't weigh cases. If I do, it's for target Cades and I will offen only use 1 case, or tops, ten cases as near identical as I can get them.

[Scharfschuetze]

I used to prep and weigh LC Match cases for long range matches. Checking my notes for LC 88 Match, the average weight per case was 177.8 grains. Might as well call it 178 grains.

Thanks to UNcle Sam, I always had more brass than I really needed so if a case came up more than a grain over or under, it got tossed into the short range brass for the 200 and 300 yard events. When sorting for the long range brass, it's surprising how few cases didn't make muster and only five or six per hundred or so were outside of my arbitrary standard.

As an aside, when turning in 7.62 NATO brass after training, we were required to turn in X pounds per X number of rounds drawn. When I worked out the pounds required in grains, the per case weight was 180 grains with primer.

[10mmShooter]

Waco,
My LC-07 brass runs 175.9 prior any trimming raw(deprimed) a 40 round sample of brass ran .79 gr SD and spread of only 3 grains... so not bad for regular GI brass. So no I don't sort by weight. In my M1a with 40.5 grs of IMR 4895, they run 2550 fps, with an SD of 19 fps and ES of 55 fps. I shoot at 300 yrds. So for my application sorting by weight is not going to gain me anything.

[waco]

Waco,
My LC-07 brass runs 175.9 prior any trimming raw(deprimed) a 40 round sample of brass ran .79 gr SD and spread of only 3 grains... so not bad for regular GI brass. So no I don't sort by weight. In my M1a with 40.5 grs of IMR 4895, they run 2550 fps, with an SD of 19 fps and ES of 55 fps. I shoot at 300 yrds. So for my application sorting by weight is not going to gain me anything.

I'm running 175gr SMK over 44gr of IMR4064 at 2600fps and shooting a 18"X24" plate at 900 yards. Rem 700 is the rifle.
Just wondering if I could make things just a little better. For me, it's hard to know if it's the load that screwed up or the idiot behind the rifle! This last summer I put five rounds on that plate that measured right around 15"
Less than 2 MOA at that distance for me is outstanding. This a box stock 700 as well.

[Scharfschuetze]

It really takes an accurate rifle at long range to benefit from case prep with all the details attended to; but it sounds like your rifle might be a candidate Waco. Most shooters probably have no need for the extra effort, but if you do shoot at 600 yards and beyond with a good rifle, then it is probably worth the effort.

As is often said about accuracy: "The Devil is in the details."

One will never be quite sure if that called 10 at 3 O'Clock that ends up a 9 at 9 O'Clock was from an unseen wind gust or an odd case in the mix. At least when the cases are all uniformed it is one less variable in the equation. Confidence in your ammo is important when taking that shot at a fine game animal or on a hot and sweaty day on the 1000 yard line.

[country gent]

I sorted LC 2 ways 1) by wieght and 2) by neck thickness variation A neck tha isnt even all the way around can cause fliers also. It seems to get worse as it goes into the case head also. Sorting by wieght can be a real benifit at long ranges, 800 900 and 1000 yds will show it in groups and scores. I also uniformed primer pockets to depth and flat on long range brass. Deburring flash holes also can make a diffrence on some cases. Wiegh the cases to 1 grn or so and then do the prep work on the good ones, if necks have alot of run out (over .0005) lightly neck turning to true up then deburr and load.

[waco]

I sorted LC 2 ways 1) by wieght and 2) by neck thickness variation A neck tha isnt even all the way around can cause fliers also. It seems to get worse as it goes into the case head also. Sorting by wieght can be a real benifit at long ranges, 800 900 and 1000 yds will show it in groups and scores. I also uniformed primer pockets to depth and flat on long range brass. Deburring flash holes also can make a diffrence on some cases. Wiegh the cases to 1 grn or so and then do the prep work on the good ones, if necks have alot of run out (over .0005) lightly neck turning to true up then deburr and load.

I just got a Forster hand held neck turner. Have not done any .308 cases yet but I'm looking forward to prepping some brass for this spring/summers camping trips. This is where I get to shoot at distance. I will take the advice and see how it goes. Thanks a lot.
Waco

[DR Owl Creek]

I sorted LC 2 ways 1) by wieght and 2) by neck thickness variation A neck tha isnt even all the way around can cause fliers also. It seems to get worse as it goes into the case head also. Sorting by wieght can be a real benifit at long ranges, 800 900 and 1000 yds will show it in groups and scores. I also uniformed primer pockets to depth and flat on long range brass. Deburring flash holes also can make a diffrence on some cases. Wiegh the cases to 1 grn or so and then do the prep work on the good ones, if necks have alot of run out (over .0005) lightly neck turning to true up then deburr and load.

+1

Before I weight sort mine, I size and deprime, trim to length (+/- .1000"), and then ream the primer pockets on any pieces that have crimped primers. I use my Lyman Universal trimmer with the primer pocket reamer attachment, and set the cutting depth so all pieces are reamed to the same depth.

I like to use a sample of at least 100 pieces to determine what the average weights are. I went over my loading notes, and came up with the following:

LC '64 NM 182.2gr. Avg. ES 3.6gr
LC '71 Match 180.2gr Avg. ES 2.8gr
LC '77 Match 178.3gr Avg. ES 4.7gr
LC '79 Match 178.7gr Avg. ES 1.8gr
LC '84 177.6gr Avg. ES 3.7gr
LC '85 177.8gr Avg. ES 2.7gr
CAVIM '90 174.5gr Avg. ES 3.8gr
MC 7.62 173.9gr Avg. ES 2.0gr
Remington 165.9gr Avg. ES 3.8gr
Winchester 157.5gr Avg. ES 1.4gr

Using a digital scale, I can then weight-sort 500 pieces of my brass (& bullets, etc.) in about 45 minutes. I don't think that is too onerous of a job. I, however, don't like measuring the water capacity of the brass cases, particularly on my digital scales, and think that is too time consuming. I've found that weight sorting of the brass into similar weight classes can give a fairly close approximation of the actual water capacity for most of the pieces. If I wanted to get the best accuracy at longer ranges like you're talking about, I would sort the 500 pieces you have into .5gr weight classes, and use the lightest and heaviest pieces for foulers, etc. That .5gr weight class variation should then only give you about a .1gr difference in the actual powder capacity for most of the remaining pieces. For smaller lots of brass, I would probably go with a 1.0gr weight variation on the brass weights.

The next thing I was going to recommend was checking and turning your case necks to help insure consistent neck tension, but it sounds like you have that covered. After that checking concentricity... Then adjusting AOL's... Then possibly trying different primers...

Is all of this really necessary? It depends on how far out you're pushing it, and how particular you are. I like to make sure my loads are the best and most consistent I can do, so I can concentrate on my shooting. Working on all this stuff also gives you a lot more trigger time too, so I think it's a win-win situation.

Good luck,

Dave

[waco]

Well, I just finished loading up 20 rounds after I sorted, weighed, swaged, deburred flash holes, uniformed primer pockets, and turned necks. 175gr SMK over 44.0gr IMR 4064 with a WLR primer @ 2.900"

At right at 402gr 6 random loads were weighed and they are all within 2gr of each other. This load already shoots well but I'm excited to see if the extra brass prep shrinks group sizes at all.

It might not show up much at 100 yards, but my plate steel at 900 might be a different story.

[CHeatermk3]

The first thing I do with a new lot of brass intended for match level shooting is to check for case wall uniformity. I don't have a ball mike (yet) but my buddy lets me use his. Then I mark the thinnest part of the case with a small notch on the rim for an index mark. Then trim to length and deburr then knock the high spots off with my neck turning tools (assuming there is variation). deburr the flash holes and uniform them too. You want the primer flame as regular as possible. Then I weigh each case and number them e.g. 1-100 in ascending order for weight and record this data in my notes. when loading for a 100-200 yd match I use all my cases and all my castings--matched by weight cases and boolits both. I make a small mark in each mould cavity and line the boolits' witness with the trued case's witness, heavier boolits go into the lighter cases. The finished rounds go into my ammo boxes in order, lightest cases/heaviest projectiles first, and shoot them in order (except foulers which are made of cull components. I load each round singly and try to get the witness mark in the same orientation in the chamber every shot.


All in an effort to reduce shot-to-shot variation.

Easier done than typed, actually.

[Scharfschuetze]

The neck turning will result in reduced bullet run out and I guess that's why we do it. For my really serious long range 7.62/308 loads for state, regional or international levels, I check the run out and discard any round with +.004 or more.

I have run a few tests that indicate if you orient the run out the same way for each shot, groups will remain fairly good even with run outs up to +.006. A permanent Sharpie marker is a good way to mark the high side of the round and I chamber that at the 12:00 O'Clock position when chambering the round.

I might add that if a case neck needs more than the usual amount of turning, it is probably a "banana" case that will exhibit its out of kilter neck dimensions throughout the case. I give those the toss, but they are probably adequate for less demanding shooting stages or events than the really long range matches. I like to see a case neck that requires no more than 3/4 of its perimeter to be uniformed. I just like to whisk of the high side and call it good.

The nice thing about using LC cases as once they are uniformed, they last a long time when neck sized and only used for long range shooting.