Shiloh Rifle Forums

In another recent thread SSShooter (Glenn) posted, “Sorting by volume can be quite laborious. Weight-sorting is much faster/easier and likely good enough for most shooting, other than Schuetzen benchrest.”

Since I recently finished the process of preparing 199pcs of new Remington .45-70 brass for a Browning BPCR I thought I’d sort them by weight to see what the spread looks like. Without running a statistical analysis of the results it’s pretty obvious the mean is approximately 188.9grs with a spread of approximately +/- 1.1gr. I’m considering grouping & marking them by weight – probably 3 groups of 65pcs or so since a match typically requires 60 cases. Will it make a difference? We’ll see if/when I get around to running a good comparison. BTW, the 2 cases to the left weigh 187.3gr & 187.5gr

It would also be interesting to compare the weight spread vs. Starline and Winchester brass, but I don’t have any.

Wayne

Wayne, your cases look like when I weigh .22 lr ammo.

Wayne,
It would now be interesting if you were to take those weight sorted batch of cases and
re-sort by Volume, first marking the weights of the cases so as to keep track of weights vs volumes.
Would help to determine any relationship between the weight and the volume of the cases.
It also might be especially interesting to check the Volume of those two really lightest cases
vs the "main spread cases"
beltfed/arnie

Check volume at each end and center. See how much difference.

I use a small triangular jeweler's file to put small notches on the rim of cases within a weight lot. After cleaning is easy to sort into loading trays or whatever simply by looking at the number of notches on the edge of the rim. Bit of a pita to notch, but only need to do so one time. As I sort by head-stamp after cleaning, is no additional work to sort by notch count at the same time.

Gussy wrote: ↑Wed May 20, 2020 3:51 pm Check volume at each end and center. See how much difference.

Will do. I sure am not going to them all for volume.
Wayne

SSShooter wrote: ↑Wed May 20, 2020 4:21 pm I use a small triangular jeweler's file to put small notches on the rim of cases within a weight lot. After cleaning is easy to sort into loading trays or whatever simply by looking at the number of notches on the edge of the rim. Bit of a pita to notch, but only need to do so one time. As I sort by head-stamp after cleaning, is no additional work to sort by notch count at the same time.

Glenn,

I use a Dremel tool with a thin diamond blade to quickly cut notches in the rim. All 200 were done in a few minutes.

Wayne

Wayne, I doubt if you'll see any advantage in separating these. It seems you've got a good batch of brass, extreme spread 2.2 grains. If they were mine I would mark the two odd ones for foulers and load and shoot the rest

Following are the results of measuring the water volume of one on each end and one in the middle. The 1st number is the case weight in grains the 2nd number is the water volume weight in grains. After primers were inserted a syringe was used to add the water and stopped with the reflection of the desk lamp on top of the water column formed a convex (rounded) surface with the last drop.
187.6 - 80.8
188.9 - 79.5
190.0 - 79.0

So there's absolutely no question in my mind that the case weight directly correlates to the case volume. Is it significant enough to make a difference?
We'll see.

Wayne

I believe that cartridge brass is substantially heavier the BP. I do not remember the ratio, but if I have cases that weight within
3 grains of each other, I consider them to be the same weight.

They all shoot the same for me.

Keep on hav'n fun!
MikeT

BTW, there's a typo in the case water volume measurements. The lightest case actually weighed 187.3gr. Therefore the corrected measurements are (case weight in grains - water weight in grains):
187.3 - 80.8
188.9 - 79.5
190.0 - 79.0

Wayne

first comment is, how do you know the external measurements of all cases is the same.
this is a hard one, and they must be to measure comparative capacity.
second thought is that 2 gn capacity will give a noticeable difference in compression in about a 70 gn case.
probably more so in a short fat case like 50 cal than 40 cal.
how much does this matter.?
if you size your brass, different metallurgy might induce different case dimensions, hence capacity.
a big question.
bruce.

Bruce, the density of brass is in the area of 8.5 gm/cm3, as compared to 1 for water. I think your comment on external dimensions is pertinent; if identical, the internal volume differences could not be nearly as great as Wayne measured. It would be interesting to mark those 3 cases and re-check to water volume differences after they've been fired.

Wayne, what was the difference in lengths of those three cases? Any difference could also potentially skew the results.

Clarence

But if you're putting an identical quantity of powder in each case, and compressing and wadding them the same, and seating nearly identical bullets, do micro variations in the length of the powder column matter?

Guys,

When I said I was finished preparing new brass I should have said finished preparing and fireforming new brass. Since they were all fired once and only cleaned in a tumble with ceramic media the outside dimensions are the same. Generally fireformed brass length will vary by a few thousands. Knowing that any length differences will affect the measurement, I did double check the length of the three that were water volume measured. The lengths were identical to within 0.001". Sorry for not including the additional details in the initial posting.

Wayne