Sorting brass by weight questions

[TroyMN]

How do most sort brass? I want to keep similar weights together. I also want to keep track of the number of times fire. My problem is somtimes I shoot 20 rds at the range somtimes 40 or more. I do not shoot matches where the round count is consistent so I know how many to load...
Here is a picture of my .308 Winchester Lake City 07 brass. Sorted by .1 grains, how would you "box" them up or keep them organized? I have several 50round ct boxes I will use. How many,, what weights do you start just tossing ie 180, 178.0, 176.0(+),173.6(-)ect. Thanks Troy

 

[pdhntr]

Keeping it organized can become a real headache can't it?

I can't help much with the weighing, but I will relate how I keep track of the number of times the case has been fired.

I use an ergonomically modified, highly specific tool to mark the case head each time I process the case. (each time it is fired). I have been using this method for many years and I can find no down side to it, other than it is another step in processing. When I process a case, the first thing I do is mark the case head. You just use the tool to put a radial scratch on the case head. The number of scratches is the number of times it has been fired.

I use a block of wood with various size holes drilled in it to hold the case as I mark it.

The following photo is of a case that has been fired three times.

The next photo is the tool with the ergonomic modifications, and various holes drilled in my work bench.

Yup..........it's a sharpened screw driver.

Jim

 

[Kingfisher]

I do the same thing only I make a little notch in the rim with an angled jewelers file. Your "ergonomic tool" makes a cleaner mark though. Like that idea and I happen to have a couple of those. Question is, how hard to you have to hit it to make the mark?

 

[bricktop]

I was using a center punch to put a dot on it for a while.

 

[243winxb]

Buy 100 minimum new brass. FL size, trim, uniform flash hole, outside neck turn, chamfer case mouth. Sort by 1/10 gr. Make lots with a 3/10 gr spread. With Rem. & Win. brass you will get a few, maybe 5 each, that are very heavy & very light. These are the brass that makes the flyers.

 

[pdhntr]

.......... Question is, how hard to you have to hit it to make the mark?

Don't hit. Scratch. Hitting might bend the case.

With the spent primer still in the case, pull the sharp leading edge of the screw driver from the primer to the outside of the case. Use a quick firm motion and you will get a good scratch that will last for the life of the case.

Getting a good sharp "V" on the end of the screw driver is key.

Jim

 

[Forum Boss]

We recently loaded some 6mmBR with Lapua 90gr Scenar Ls. Blue Box Brass was trimmed and chamfered -- no other case prep. No sorting.

Out of curiosity. We weighed 10 loaded rounds. Here are measured weights in grains:

xx6.6
xx6.6
xx6.7
xx6.6
xx6.4
xx6.5
xx6.6
xx6.7
xx6.6
xx6.5

Those are weights with bullet, primer, Varget powder (thrown by ChargeMaster) -- everything. Spread was 0.3 grains, 5 of 10 were 'dead on' same. The spread was 0.11 % of total weight. (one tenth of one percent).

I'm not knocking weighing your brass with other brands. But we were amazed at the consistency with this Lapua brass and Scenar Ls.

 

[savageshooter86]

there are some posts out there that state weight sorting cases does not ensure same internal capacity. I checked this out and was happilly surprised to validate this information. Weighed 10 cases to get H20 capacity. Then went back and found the ones that had the same internal H20 and then compared the dry weight of the cases. Guess what......they were not the same. Varied as much as 2 full grains. So that shows me if I weight sort cases that really does not do anything for me except to cull out extreme variances

Just thought I'd share. Since at one point I sorted over 500 cases by weight. Now doesn't seem it would help all that much for me

 

[jlow]

I’ve done this experiment and posted it here. The answer is it depends. For example, there is an excellent correlation between brass weight and capacity for LC09 556 brass. However, there is a poor correlation between Win 308 brass and capacity.

The other unanswered question though is looking at the LC09 brass which has excellent correlation between weight/capacity, testing a series of cases which varied by as much as 1.5 grains, with everything being the same, I found a relatively poor correlation between brass volume and MV – correlation coefficient of 0.12 using 25 cases. :

This surprises me as I am pretty sure that changing case capacity by changing seating depth has a pretty significant effect even with minor changes. It is true that that method does change the distance between the bullet and the crown but still…. Wonder what other’s experience has been.

 

[TroyMN]

Thanks for the replies. I loaded up some using the middle brass or same weight. I notice (thought I noticed) some looked to come up to the necks higher and others are a little lowerer. I remeasured the powder thinking it was off, but it measured correct. Maybe this is the internal capacity variance....
Some time I will fill some up with power and separate the full ones and lower level ones then do the water test. Do you use water or an other liquid (alcohol) with lower "contact angle" to reduce the chance of air bubbles inside the case?
Thanks again
Troy

 

[jlow]

As mentioned previously, the Win 308 brass weight did not track real well for me in terms of volume. Here is my data for the 556 LC09 brass and 308 Win brass. The 556 is on the left and 308 on the right. X-axis is weight and Y-axis is volume. You can see the 556 correlation co-efficient is 0.7239 vs. 0.1885 for the 308.

In terms of how high the powder comes up the neck, it is a bit difficult as depending on the granule shape, you can have significant voids in there. You can decrease this a bit using a long drop tube or vibrating the case or tapping it. When I did the test, I put in a spent primer and used rubbing alcohol (70% isopropyl alcohol) which works well and does not evaporate that fast or leave a meniscus.

 

[Beau]

.1 gr? Ooh-wee! OC! ;D

FWIW, practice is what the extras are for.