This wasn't really a "study" I now weighed 300 cases and wanted to post the results for people here to reference.



After adding more cases to the sample, the graph became more gradual, without gaps between one weight and another.



"I" indicates one case per each wieght:



171.0 - I(1

171.1 - 0

171.2 - I(1

171.3 - II(2

171.4 - III(3

171.5 - IIII(4

171.6 - IIIIIIII(8

171.7 - IIIIIIIIIIIIIIIIII(18

171.8 - IIIIIIIIIIIIII(14

171.9 - IIIIIIIIIIIIIIIIIIIII(21

172.0 - IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII(32

172.1 - IIIIIIIIIIIIIIIIIIIII(21

172.2 - IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII(63

172.3 - IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII(34

172.4 - IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII(34

172.5 - IIIIIIIIIIIIIIIIIIIII(21

172.6 - IIIIIIIIIIIIIIIII(17

172.7 - IIIIIIIIIIIIII(14

172.8 - 0

172.9 - II(2

173.0 - 0

173.1 - 0

173.2 - 0

173.3 - I(1

173.4 - I(1



I have 500 of these cases, which over time I will weigh all of and group to .5gn or thereabout for my target shooting, the rest use for hunting and testing bullets.



Now it seems I have a very good group of cases to work with...



Hope someone finds this more interesting than I found sitting and weighing them all.

Good work. Your plot looks reasonable to me for 100 pieces and assuming random effects that influence the weight. It is quite possible to have two sets of average values, called a bi-modal distribution, that can make it look like you describe.

steve505

Here's my 6.5-284 Lapua brass weight distribution from a box of 100:

194.5 - I
194.6 - 0
194.7 - 0
194.8 - 0
194.9 - 0
195.0 - I
195.1 - I
195.2 - 0
195.3 - II
195.4 - I
195.5 - 0
195.6 - II
195.7 - III
195.8 - 0
195.9 - 0
196.0 - II
196.1 - II
196.2 - II
196.3 - IIII
196.4 - II
196.5 - II
196.6 - IIII
196.7 - III
196.8 - III
196.9 - IIII
197.0 - IIII
197.1 - IIIIII
197.2 - IIIIIIIIIIII
197.3 - I
197.4 - IIII
197.5 - IIIII
197.6 - III
197.7 - IIII
197.8 - IIIII
197.9 - IIIII
198.0 - IIII
198.1 - III
198.2 - III
198.3 - I
198.4 - I

Hey EXPRESS, That does speak well for their consistency.

I'd pull the 171.0<->171.6 cases into one Test Lot of 9. Real nice cause you can get 3 sets of 3-shots.

And I'd pull the 172.6, 173.3 and 173.4 cases into a separate Test Lot of 5 cases.

That allows you to do all kinds of Load Development and Pressure Testing.

The remaining cases are then less than 1.0gr apart in weight and you can still sort them into Lots exactly alike or very close together.

I do the same thing when I buy new cases, but normally get 300-500 at a time from the same Lot and combine the data.

I have a question for you folks that wiegh the cases and such.

Do you do it before or after case prep?

The reason I ask is that when I purchase case I do a full prep on them BEFORE I wiegh them. Following are my steps

1. tumble to clean if needed and visual inspect for gross problems (ill formed mostly)

2. run all through full length sizing

3. Trim to given length

4. deburr primer flash hole

5. true primer pocket

6. wiegh them and segarate by wieght.

My thinking on this is that this gets them to all the same dementions and I have removed all the brass I need to prior to first firing. I guess if I really fanatical I would do neck wall thickness and uniformity but I do not. This seems to make sense to me, but just woundering what you all think.

Pick: For many, many years I used to buy 200 more pieces of brass than I wanted to dedicate to a particular Rifle. If I wanted 200 pieces of brass for a particular Rifle I would buy 400 pieces. If I wanted 500 pieces I would buy 700 etc. Then (on a mechanical beam scale) I would weigh them all! Dividing them up into light - OK - heavy groups. I would keep the middle weight group and bag up the 100 lightest in one bag and the 100 heaviest in another bag. I would then sell these cast offs at the local monthly Gunshow. People were told of the weight selection process and bought them up eagerly.

No I did not prep them before sorting them by weight.

I achieved my goals accuracy wise with this method and have only in the last few years had to quit doing it for my new Rifles. Reason: I now live far from civilization and don't get to sophisticated Gunshops as much as I used to be able to buy the bulk brass.

Now I am finding I can achieve excellent accuracy using non-sorted brass in my factory Varmint and Custom Rifles! So there - on that.

Having said that I must tell this story my friend Louie out in the Seattle area relayed to me last fall! Louie has this custom 220 Swift built and it comes time to do load testing. His heavy barrel Rifle had a big variable scope (6.5X20 as I recall) and he is an excellent and disciplined shooter. Upon testing he notices almost all loads have double groupings on the target! He goes through weeks of torment and repetitive fixes of the Rifle and variations in loadings (I've been there!). His exasperations continue til one day he is putting the spent shells in his loading block upside down. He then notices his Winchester brass (that he had bought in bulk!) had two completely different head stampings! Different vintages? Anyway once the brass was seperated the double grouping ceased!

Over the years hanging around gunsmiths and gunshops and attending Bench Rest Matches I have gotten the distinct impression that in the 6mm PPC caliber the brass that Sako offers is clearly inferior in quality. Well last year I brought online a factory stock Sako single shot bolt action Varminter in caliber 6mm PPC! I used Sako new unfired brass and Varmint style bullets in my load development! The Rifle has a 24X Leupold scope and is like I said factory stock overall. I came up nearly immediately with two groups of 5 shots each at 100 yards of .212" and .226"! Now if I were to have expected anything more rewarding than those groups my expectations should have been described as "unrealistic"!

So if Sako brass is inferior then I am very satisfied with "inferior" brass!

I have lots of friends that compete in various Rifle disciplines and anymore it seems the only ones that sort brass are the BR types. Now maybe that is just my circle of friends but I am starting to loose my urge to sort brass!

It has been at least 15 years since I tested for myself the effect on my accuracy using sorted brass and unsorted brass. I do recall the Rifle and the results though. It was done with my ultra accurate Remington 40XB-BR in 222 Remington. I used Federal brass in my test and only shot four 5 shot groups. Two with the sorted brass and two without. The sorted by weight brass shot a couple of hundredths (average grouping) less than the unsorted brass! But one of the unsorted groups was smaller than one of the sorted groups. The sorted brass group average again was .02" smaller. Is it worth it? Is my ultra small sampling test worth much - I doubt it looking back on it now.

If it gives you confidence though - I say do it!

Hold into the wind

VarmintGuy

VarmintGuy:

You'e just about right. That .020 sounds about right and you'd never see the difference from sorting brass from a good lot in most rifles. Even good shooting varmint rifles would be hard put to show the differnce. But that .020 is a BIG difference when you're trying to win a benchrest match.

I don't think that Sako brass is greatly inferior to Lapua brass. When you're talking PPC brass the Sako USA is slightly smaller in capacity to the Lapua .220 Russian and the old Sako .220 Russian brass from which most benchrest PPC cases are formed. That Sako USA brass was made for the Rifle in which you are shooting it. And I would think it does a great job. We could make it shoot in the benchrest guns too by changing the chamber dimensions a little. Then it was a matter of finding a working load. We had to do that in the early 90's when Sako quit importing their old 220 Russian brass and there was no Lapua. If you mic the 2 cases you'll see what I mean.

knobmtn

Thanks for the replies, but you still have not answered the basic question.

Do you sort by wieght prior to case prep or after? And what is your opinion on it?

Was intresting reading though.

Hi pick. Greetings from Somerset County. Where's Reeders?



I always sort by weight after visual inspection, and prior to anything else. My thinking is that I'm not going to trim a grain of brass off there when cleaning the flash hole or trimming the cases to length.



Don't know that it matters that much whether it's done before or after, tho.., unless you're sorting by tenths of a grain



R-WEST

Reeders is in the Pocono's in eastern PA..

It seems as if I am about the only one that does any case prep prior to wieghing.. Does not surprise me though as I have always been a bit 'different' in the way I do things

I fire form my brass before I do much of anything to it.
That said, one of the things I don't do is weigh brass, before or after firing.