Ladies and Gentlemen,

We have been sorting out some brass for trhe 220 Swift.

We have some brass from Norma and some from Winchester.

We follow the same proceedure when we get new brass.

1. Full length re-size
2. Trim to minimum case length
3. Uniform the flass hole
4. Uniform the primer pocket.
5. Weigh the cases to segregate them.

We had a total of 1,678 Norma cases, and their weight distribution was as follows:

Weight in grains, quantity in that weight, percentage of total.

160 - 143 - 8.52
161 - 98 - 5.84
162 - 53 - 3.16
163 - 212 - 12.63
164 - 864 - 51.49
165 - 305 - 18.18
166 - 3 - 0.18

Winchester brass, we had 592 cases.

156 - 18 - 3.04
157 - 268 - 45.27
158 - 240 - 40.54
159 - 66 - 11.15

You start with a mismatch. Randomly pick 592 Norma cases and retest.

I would not expect any of the manufacturers to product cases of the same weight or volume.

The specific gravity of brass is 8X the specific gravity of powder.
So a grain of powder takes up 8X the volume of a grain of brass to put it into perspective.

You are wasting your time trimming the new brass.
Measure the lenght of the chamber to the end of the neck. It will be significantly longer than your longest cases. Plus the cases will get shorter when fired and then longer when resized.
Check them for lenght only after firing once and resizing the first time. You will probably not need to trim other than to square up the case mouths.

for you brass weight distribution I would make a large lot of brass out of the middle of the distribution. The outliers can be used for load development. If you blow a primer pocket you will not lose a case in the middle of your best lot.

Gentlemen,

We are not trying to see which brass is better.

I was just showing how the brass turn out.

We have to eliminate all the variables, and trimming the cases brings them to the same size.

seperating them into weight groups, eliminates another variable.

Looks like you are saying, with this limited sized sample (which is much larger than I have done... Walter must have been busy...) that Winchester is somewhat more consistent than Norma- which somewhat surprises me.

Interesting piece of data...

Have you done this with other (big game) cartridges as well?

Sample sizes do not have to be equal for a statistical comparison. 600+ of each is a valid sample size, and more to enough to run NOVA analasis. But I don't see a need to fire up SAS, the MK1 eyeball will tell you the difference is statisticaly significant.

Saeed, thanks for the report.

Thanks for sharing the data.
Why is it hard to believe that the Win. has a closer distribution than the Norma? What would be of more interest to me is the head hardness off each. After all the Swift is no pressure light weight.
The idea of a 22 Swift with a long throat and really fast twist would parallel contemporary activity for long range shooting and long lead free bullets.It could also more adequately facilitate the 22 cal. deer hunters. roger

This is somewhat off subject but does pertain to weight segregated brass and the use of. I thought it might be of interest to some but I am sure I was not the first to do this.

About a month ago I decided to run a little informal, "highly" non-scientific experiment of my own using weight segregated Winchester brass.

I opened up a new bag of 50 Winchester cases and weighed each and marked and sorted them accordingly.
I then took the three lightest new un-fired cases of a lot of 50 and worked up a load using the same 3 cases over and over. I used the 3 lightest cases of the same weight under the assumption they had the most initial volume and thinest case walls.
After firing, I then re-sized the necks only with the Lee Collet sizer. As is the norm for most shooters, I worked up a load based on max. amount of a given powder for that cartridge (30-06) and rifle, which gave me the best "safe" accuracy at 100 yards.

I then lined up all of the remaining cases from lightest to heaviest (with their weight marked on the case), in a reloading trey. I began loading each case and as each case became heavier I simply reduced the powder charge by that amount. In other words if the case was .8 of a grain heavier than my original 3 "benchmark" cases then I reduced the original load by .8 tenths of a grain and so on.

I proceeded in this manner all the way through reaching cases that were as much as 4.5 grains heavier than my original "benchmark cases". I then fired these over a chronograph at 100 yards. The results were pretty amazing to me as the accuracy remained excellant for quite a ways up the ladder. The velocities would vary as much as 200 fps. as I progressed but the accuracy held on until I reached the point where the cases were around 1.5 to 2.5 grains heavier (which reduced my loads by 1.5 to 2.5 grains).

What got start on this experiment was, some time back, I shot up a box of Hornady Custom factory loaded ammo that was very accurate in a particular rifle I have. I got to thinking about it and realized that mass produced ammo WAS NOT going to have segregated brass. It would be un-economical. But the ammo makers could Quality control the final cases by total weight rather than volume in the manufacturing process. Now I am sure they are using highly customized powders that are not very sensative to volume differences. Something that is probably not available to the average consumer despite what any of the powder manufacturers claim they are selling. There are industrial trade secrets.

Again there was nothing scientific about this process and it could have just been a not so average day where all of the stars were aligned just right. But the results were somewhat surprising to me if no one else.

quote:

In other words if the case was .8 of a grain heavier than my original 3 "benchmark" cases then I reduced the original load by .8 tenths of a grain and so on.

Rae,
This is an interesting test.
I would suggest that you think about the difference in density of the powder vs density of the brass. Brass is about 8X more dense that powder. That is a grain of powder takes up 8X more volume than a grain of brass.
It would be interesting to test various case weights with exactly the same powder charge and compare to slight stair stepping of the powder charge in cases of exactly the same weight.

That is a good suggestion SR. I'll give it a go some time soon.

FWIW I'm not one to segregate brass in the method I described. Fact is I never do other than by brand and other obvious reasons. Having said that, I am certain the extreme fringes of brass weight account for those oddball-goofy and un-explainable flyers that one gets from time to time. You know, the ones that are 6" away from the others........

quote:

Originally posted by Rae59:
That is a good suggestion SR. I'll give it a go some time soon.

FWIW I'm not one to segregate brass in the method I described. Fact is I never do other than by brand and other obvious reasons. Having said that, I am certain the extreme fringes of brass weight account for those oddball-goofy and un-explainable flyers that one gets from time to time. You know, the ones that are 6" away from the others........

Yeah I know it has to be the brass or the rifle or the bullet or ... anything but me.


As far as sort brass goes. If I have a benchrest or varmit type rifle and a huge lot of brass I will sort it just out of curiosity.
Once I do that the outliers are used for load development. The rest are grouped in to large lot of similar weights. I would never think about this without a digital scale.