Weighing brass


PDA






NotSoFast
December 27, 2008, 02:18 AM
When you weigh your bottleneck cases, do you weight them deprimed or with a new primer installed? Or is there some other way you to group them according to weight?

Up to now I've been weighing them with new primers pressed in but I got to thinking today this might not be the best way to group them. Thoughts?

If you enjoyed reading about "Weighing brass" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
green3845
December 27, 2008, 07:17 AM
I'm sure everybody has their own pet method, here's mine!

I usually start with new brass, so I don't have to contend with differences from combustion residue from the powder or primer. If your brass is really clean from tumbling for a decent amount of time, you should be OK for any purpose other than benchrest competition.

I perform all prep steps--sizing, trimming, primer pocket reaming, flash hole deburring. If it is virgin military brass, I also swage the primer pocket.

I then begin weighing, after all of the brass has been "uniformed".

I weigh a few and get an average, then accept a certain range either side of the average.

For .223 size cases, I accept .5 gr. either side of the average.

For a .308 size case, I will accept 1.0 gr. spread either side of the average.

These uniformed and weight selected cases are bagged together and only used for my long range loads for competitive shooting. For 200/300 yard shooting, for my High Power competition purposes, I haven't found weight selected cases are needed. With no sorting, or prep, I can still get 1/2 MOA with proper load development, which is more than adequate for High Power competition.

moooose102
December 27, 2008, 07:52 AM
i am rather new to the accuracy game. but i dont see the point in weighing brass. isnt it more important to know the internal volume of a given set of cases that the weight? if the head is thicker, it would weigh more, but the volume could be quite different. i am going to cc my cases, or at least that is what i have planed. after firing every round so it fits my chamber. and neck sizing only. am i wrong in thinking this is a more accurate way to go?

243winxb
December 27, 2008, 09:09 AM
Take 100 new brass (deprimed)and use a Lyman Flash Hole Uniformer Tool on them. Weight each case, seperate by 1/10 gr. Then i see what weight range most fall into. I make batches that are closest together to get at least 25 in each batch for the type of shooting i do. I did a test to see if weighting brass mattered. Using winchester brass 243. I took 5 very heavy and 5 very light. Shot groups with both. The i took 3heavy 2light for a group. 2heavy 3 light for a group. The cases with the closest weight made the best groups. Weighting brass works.

243winxb
December 27, 2008, 09:21 AM
isnt it more important to know the internal volume of a given set of cases than the weight? IMO No. A rifle chamber has a volume. This volume runs from the bolt face to where the bullet seals the bore. Any matter(brass case) of different weights placed in this volume changes how pressure reacts. Therefore you want the exact same matter/weight in the chamber volume each loading. Remember on firing the case becomes as one in the chamber. If the chamber walls & bolt face were not there to contain the brass on firing, the brass would blow apart.

plinky
December 27, 2008, 09:47 AM
I've been giving this some thought myself. Never have weight sorted brass before but I have a new lot that I want to do right.

My plan is to neck turn for consistancy (or not if unneccesary), deburr flash hole, fireform, trim then weight sort. I'm thinking that the brass will do most of it's stretching and moving around on the first firing so I won't sort them till after that. Otherwise the first trimming might unequalize my sorted cases.

So this is what it's like to be anal....:D

Walkalong
December 27, 2008, 09:52 AM
Weight each case, separate by 1/10 gr. Then i see what weight range most fall into. I make batches that are closest together to get at least 25 in each batch for the type of shooting i do.
Basically what I do. This 50 in the first picture illustrates it. 50 cases fully prepped and weighed. The 21 cases in the second pic vary by .6 grains. That is one of my bench blocks. My other one is home made. Necks turned .0084 to fit a .261 chamber. The 3rd pic is my home made Load Box.


I sort my .222 Mag brass within 1.0 grain. Good enough for me.


So this is what it's like to be anal....:D
It's a start. ;)

.

NotSoFast
December 27, 2008, 08:10 PM
So I take it I need to weigh them after depriming them, sizing them and trimming them. Thanks, especially to you Green3845.

rg1
December 27, 2008, 08:14 PM
Here's a great article on case prep for maximum accuracy:
http://www.6mmbr.com/jgcaseprep.html

If you enjoyed reading about "Weighing brass" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!