brass weight range

[jpretle]

For those of you who weigh cases, what precentage of average weight of a lot, do you accept? I've weighed a lot of Win 22-250 brass and I can take out the few extra heavy and the few extra light, but how deep should one cull?

 

[brian427cobra]

I'm not a BR shooter, so unless your shooting that game I don't beleave case weight has a direct coralation to case capacity, I'm in a huge argument on Snipershide on this subject, sometime next year I'm going weigh all my cases on a very exspensive lab scale to prove or disprove the notion that case weight of .1 or more has a meaningful effect on FPS/Accuracy, I use a Prometheus Gen2 to weigh my charges, so exact repeatable charges are not a problem, I already have low single digit spreads with Win 7-08 and Win 243 resized to 260Rem, and off a bipod prone .3 groups are the norm at 100/200

 

[jpretle]

Where then, does that extra brass go once you re-size??? Or is that extra weight in the composition of the brass
----not additional, but just heavier???

 

[Rtheurer]

Jp
Did you weigh all your cases already? When I used to do this I had a piece of tape on my bench on the edge. For example I would have 96.1 96.2 ----- 97 97.1 and on. One time I had a fella tell me I was wasting my time as internal volume did not coralate to the external mass weight of the case. I argued that it could not be... it ( weight) has to be Some where if all the cases where sized the same on the outside... makes sense right? So I just kept on weighing knowing that my method was the right way....
Well I kept reading and hearing the same thing about internal volume. So one day I laid out a bunch of once fire brass in 223 and FL sized them, trimmed them all to the same OAL and then weighed them. Also put a Sharpie mark on them of the weight. I then did the massive task of filling all 100 cases with water and reweighing the whole batch again! It was ahuge pain in the a$$. I was convinced I would see that same bell curve as I did with the empty case weight. Well I did but it was way way way smaller on Extreme spread than the empty case weight. An extreme spread of empty case weight of over 2 full Grains was was less than .5 grains of internal volume. Along with that the MASS majority was in the middle of that Curve was very very large with just a handfull of case on the outside of that. So I proved it to myself that yes indeed internal volume is ALOT closer to the same from case to case dispite a larger ES in overall case weight.
If I was shooting Long Range benchrest I would pay more attention to this but even my long range palma ammo is loaded right out of the box.

If you really want to see for yourself you can take and do the same thing. If your like me.. sometimes I have to see it to believe it.
Dont take my word for it... try it yourself.

Hope this helps.
RussT

.

 

[th82457]

I use this general rule of thumb for my loads. On .378 case head brass I stay within 1 grain for accuracy loads. for .473 or .532 brass I stay within 2 grains. For the Norma, Lapua, Federal and Winchester this usually results in very little culling in the same lot. I have found the Remington and Hornady brands tend to vary more and I end up throwing several cases per hundred away due to variation of up to 5-6 grains. Just my 2 cents.

Terry

 

[savagedasher]

Internal volume is the best and safest. 2 gr is a huge amount if your near maximum 1/2 gr in small cartrages is the same. I find bigest difference is in manufacturers.I shoot long range benchrest we use Lapua brass when I do my brass I buy 300 rds Sort by .02 tenth of a grain total weight.I normaly end up with 100 plus in each .02 tenth .We strive for low sd 3 or less. Normal reloading same manufacture 1 grain is plenty safe. Good Shooting Larry

 

[articmp]

I used to weigh bagged remington brass. 223 Rem with a 4 grain spread in a 100 round bag was nuts. I normally seperated it within a .1-.2. , end up having about 40 out of 100 that would be in tolerence. The rest were just way out there.

 

[Rtheurer]

Larry

Do you turn your necks and then check the internal volume or do you weigh and check internal volume before you turn the necks?

Thanks for posting. I believe in your game that extra step is warrented. In a hunting rifle or even most other competative sports not as much. Unless it makes you feel better as that is important that you have confidence in your ammo.
Also like you I have found that the Lapua and norma brass seems to be a little more uniform. Sometimes the domestic stuff is real good as well. Sometimes its a pleasant suprise.

Again thanks for giving your prospective.
RussT

 

[jpretle]

Is 6g. variance pretty extreme in a lot of brass?? The brass in question was purported to be the same lot of 500.
There are 484 pieces, the lightest being 156.2g and the heaviest being 162.9. Naturally there are just a few cases
at the extremes of weight.(about 25cases) 6g. difference makes me wonder if this is just one lot of brass.

 

[jpretle]

RussT, well there is no sense in going down the road you came up. I will take your word for it. I don't have the patience to pursue all
that anyway. I am wondering if you were just lucky in having a weight varience of about 2g., though. Don't think I've ever come across
a batch of Win brass that consistent.
Thanks, for sharing your findings.

 

[savagedasher]

I don't turn necks I weigh the total case I have a reamer made with .7005 neck .130 freebore made for 105 berger Hybrids and blue box Lapua brass.The gun shoots The shooter has good days and bad. Good Shooting Larry

 

[brian427cobra]

Where then, does that extra brass go once you re-size??? Or is that extra weight in the composition of the brass
----not additional, but just heavier???

The weight of a piece of brass does not change when resized. I do neck turn all my brass to .0135, Uniform Primer Pockets, Deburr Flashhole, I would assume that the 243 brass resized to 260 weighs less than the 7-08 resized to 260 because the thicker part of the shoulder that becomes neck is turned away, I don't separate my brass, 243 and 7-08 are all mixed together. The reason I use Win brass in my 260 is two fold, 1st and for most is price, I shoot in Precision Rifle Matches(I dont like to call them Sniper because I'm not one) and its not uncommon to lose 50% of it, 2nd is Remington brass flat out sucks, and Lapua is not much better, yes I don't think Lapua is good brass, at least not there 260, Rem primer pockets only last 5-6 reloads, Lapua 4-5, where as the Win I have some have 25 reloads, I anneal every 3-4 firings. Now back to internal capacity, I have noticed that smaller cases are much more sensitive to charge weights, where as large cases are not, this maybe because of internal capacity, powder burn rates, or both, I really don't know.

 

[308sako]

I would suggest that weight alone is not sufficient to test.

Volume is a greater issue and that is what should be measured!

 

[jpretle]

I'm not saying the wt of the brass changes on sizing. Just thinking the weight of each piece of brass is due to the density/composition
of the material when each case is drawn???? If the density/composition of the material is not consistent then the wt of each case is
different. Not sure what all, drawing brass, entails.

308 sako,
Certainly a variation of 6g. in a lot of brass would have a noteable variation in case capacity, even in the
22-250 case, would it not????? And if that is the case, a proportional effect on pressure and in the end result, accuracy?????

 

[bigedp51]

The main page of Accurate Shooter has a great deal of very good information.

Complete Precision Case Prep
Preparing Cases for Long-Range Accuracy

http://www.accurateshooter.com/technical-articles/reloading/complete-precision-case-prep/

Step 8

Weigh the cases and separate by lots not greater than one grain in weight difference or about 0.5 percent.

 

[CoverDog]

I have a reamer made with .7005 neck .130 freebore made for 105 berger Hybrids and blue box Lapua brass.

A little to much eggnog ??? I'm sure you mean .2705 neck

 

[broncman]

Dangit! One more thing to obsess over!

In the middle of processing and sorting all my 223 and 308 brass for this coming year. Was wondering how much of a weight spread to sort my brass.

223 small case volume would make volume changes important. 308 for 1000yards just as important as well?

 

[articmp]

Broncman, I'd say it may be. After seeing how much vertical a man will get with just a shift of 2 or 3 MPH of headwind with the slower rounds, you are fighting a harder battle with that 308 versus the short mags and such. Gotta make sure that your load has a single digit SD to be able compete, and a cc or two of case capacity is just another thing to open the group up.
I'd weigh to sort the group out, then spend the time with the water after you get them thinned out.

 

[th82457]

For 1000 yard shooting I can not comment on how precise to be on brass weight or volume. I assumed the original post was for varmint shooting since .22-250 brass was what the original poster inquired about. While a great varmint round - I doubt you see many of those on the 1000 yd range ? Again just my 2 cents.

 

[jpretle]

dth82457, those 22-250 cases are getting opened up the 6mm. Didn't think that was important, so did not include in initial post.
I know the donut comes into play, but I will worry about that when I open up the neck and do the neck turning.