weight sorting brass.....

[mike in co]

gentlemen...in that i expect you to act like one in this discussion.

do you weight sort your 600/1000 yd brass ?

i did a weight sort on my rws 300 win mag.....100 plus pcs at plus or minus 0.5.

close enough or not ?

( for background....if your brass is not from one lot....weight sorting may not help. brass is basically a solid. if a brass case has a uniform primer pocket, no flash hole burr, the same length, the same oudside shape, then it iis my proposal that the internal volume of similar weight brass will be essentially the same. this is based on a single lot of brass where one density of alloy was used, in a set of brass froming dies.
my single venture into this was with a single lot of 223 brass that i bought. the brass was used as the basis of john feamsters book black magic. it was originally 500 pcs and just short of that when i got it. john had flyers in some of his testing , so the first thing i did was to weight sort the brass. it produced a long bell curve.
spread 89.6 to 94.5, ....long thin ends to the curve. mean about 92.1. easy to explain flyers.
i then did a full brass prep on the brass and rewieghed/sorted.
of this prepped brass i got one lot of 30 pcs that weighed the same. these i did a volume test on.
guess what ...the internal volume was also the same...h2o vol at 77degrees.

in this limited small case check, i say weight sorting counts. now i know i was using winchester cases, not lapua. norma, nor rws. i have heard that lapua 220 rus(6ppc) is very consistant, but have never checked.)


so what do you guys say ??

mike in co

 

[4Mesh]

gentlemen...in that i expect you to act like one in this discussion.

Lol
This damn board deleted another post, bugs in the reply page...

do you weight sort your 600/1000 yd brass ?

Yes

i did a weight sort on my rws 300 win mag.....100 plus pcs at plus or minus 0.5.

close enough or not ?

Close enough for the 100, not close enough for match sets says I.

( for background....if your brass is not from one lot....weight sorting may not help. brass is basically a solid. if a brass case has a uniform primer pocket, no flash hole burr, the same length, the same oudside shape, then it iis my proposal that the internal volume of similar weight brass will be essentially the same. this is based on a single lot of brass where one density of alloy was used, in a set of brass froming dies.
so what do you guys say ??

mike in co

I say, you will get argument on the volume vs weight thing. Sounds good in theory. Good enough for me, but, others here have done proofs to the contrary. (and I have no reason to doubt it)

Back in the early days of WSM's, 15 grains of variation was about normal in Norma. More in Winchester. It was horrible. Later on, 4-5 grains with a few outliers was more the norm, and so 200 pcs was enough to work with. Belted mag brass has always been much nicer for consistency for whatever reason. Perhaps they make more of it, perhaps it's cause it's thinner/lighter. I tried to keep the whole set within .1gn, but that wasn't always possible. Do what ya can.

Like everything, make it as close as you possibly can. Figure it like this, if it makes no difference at all, then I guess sorting out 10 pcs from the 100 can't be any worse.

(PS, I don't think you will see a velocity/pressure variation with that lot of brass)

 

[dk hunt 14]

I sort my brass to .01 grain and this is before any brass work is done. I believe the internal volumes to be good and have never had a bad set of brass with this method. Matt Kline

 

[4Mesh]

I think you mean .1 grains?

 

[dk hunt 14]

On the dasher i try to get sets within .01 to .03 grains. If you weigh out 500 pieces of 6 BR Lapaua, yopu can sets in this range. In the 300WSM i weigh out 500 to 1000 pieces and try to stay within .1 grains. The 6 BR brass comes in around 125 to 126 grians and the wsm is a lot heavier and doesn't weigh as good . Matt

 

[ronemus]

I did an experiment several years ago to determine just how much effect brass weight has on .223 loads. I used WW brass (sized, trimmed and deburred, primer pockets uniformed, flash holes deburred, and neck turned) , WSR primers, charges of RL-15 or N-550 powder weighed to 0.1 gr, and 75 gr A-Max bullets. Using the lightest and heaviest cases (sorted from 1000 once-fired I had on hand), I had two lots of 10 cases with a 3 gr difference in weight. The average muzzle velocity difference was 16 fps, just a bit more than the 12 fps due to 0.1 gr of powder.

I choose to sort 0.5 gr lots of brass for my long range .223 loads and 1.0 gr for .284 (larger case, 2x weight and volume), but the effect will only matter at 800-1000 yards - the vertical displacement on the target from such a small velocity change is negligible at shorter distances. Unless you control all other sources of variation, the effect of brass weight is negligible.

 

[mike in co]

same question i ask all.
was the brass from one manufacturing lot?
was the gun a br gun ?
was the powder done on a beam scale or a lab scale ?
powder on a beam is more like .2 grain spread i use less then .05
were the bullets sorted weight/ bearing length.

600 yd high power and 600 yd br is two very different games.
and yes we are talking 1000 yards.....
mike in co

I did an experiment several years ago to determine just how much effect brass weight has on .223 loads. I used WW brass (sized, trimmed and deburred, primer pockets uniformed, flash holes deburred, and neck turned) , WSR primers, charges of RL-15 or N-550 powder weighed to 0.1 gr, and 75 gr A-Max bullets. Using the lightest and heaviest cases (sorted from 1000 once-fired I had on hand), I had two lots of 10 cases with a 3 gr difference in weight. The average muzzle velocity difference was 16 fps, just a bit more than the 12 fps due to 0.1 gr of powder.

I choose to sort 0.5 gr lots of brass for my long range .223 loads and 1.0 gr for .284 (larger case, 2x weight and volume), but the effect will only matter at 800-1000 yards - the vertical displacement on the target from such a small velocity change is negligible at shorter distances. Unless you control all other sources of variation, the effect of brass weight is negligible.

 

[glbreil]

I could never understand how you know where the weight difference is. You could have two pieces of brass that weigh exactly the same and one have a thicker base and the other thicker walls. It would appear to me that those differences would matter as much at a .1 grain weight difference. I cull the extremes and use all the rest, but I am also a firm believer in the "if it makes you feel more confident it is worth while theory" so I say to each his own.

Gary

 

[mike in co]

which is why i insist it must be one lot of brass, the same material built in the same set of punches and dies. t then the bases should e the same , the walls the sme and then wieght relates to volume.

I could never understand how you know where the weight difference is. You could have two pieces of brass that weigh exactly the same and one have a thicker base and the other thicker walls. It would appear to me that those differences would matter as much at a .1 grain weight difference. I cull the extremes and use all the rest, but I am also a firm believer in the "if it makes you feel more confident it is worth while theory" so I say to each his own.

Gary