Mixing brass of the same lot number

[TackDriv3r]

I recently bought two boxes of Lapua brass, both are the same lot number. Can I mix those two boxes of brass together and make it a 200 piece batch without it affecting accuracy at tournaments?

 

[Rocketvapor]

I guess it depends on your level of shooting skill.
Can you tell the difference in unsorted Lapua brass?

 

[jepp2]

Why don't you completely prep all 200 cases, and then weight sort them.

That is what I do, and break them into 50 round "batches" based on the weight sort. Only a little time on my part.

 

[Dimner]

Has any one been able to view the brass coming off the line and being boxed? If it's all the same lot# and it's randomly picked to be boxed, having a 100 or having 200 is probably going to be the same. If I were really worried about brass of the same lot, I would either sort when fireforming or sort by volume. Either way though, I could never shoot the difference.

 

[7br]

Ditto bugman and jepp2. I do the same with excellent results. Lately I’ve been getting tighter weight variance with Peterson brass over Lapua. Your mileage may vary. I know some guys rely on water volume. I’ve never done that but they seem to get good results with that method.

 

[Chaotik]

I have not tested this, but am considering mixing 2 boxes of different lots of Lapua brass and then volume sorting them, either water weighing or using the Bison Armory case volume gauge. This is specifically for LR benchrest competition.

I typically just volume sort brass from the same lot.

 

[TackDriv3r]

Today, lapua can vary up to 2 grains in one box, and that is with a 6BR parent case. If you are competing at LR, only you can answer if that is significant.
Why don't you completely prep all 200 cases, and then weight sort them. Find out for yourself what the amount of variance is. Separate into groups of 0.2 grain variance, and that bell curve will most probably show you around a half dozen pieces that are really outliers......use those for foulers. If you need to be very particular, group the others into lots of 50 with the closest weight-sort.

Sort the brass before firing? One box is still unopened, I have already fired about 60 cases, labeled them as fired 1X on the other box. Sheesh

Might as well shoot the remaining cases, and dry weight sort all 100 fired cases with the spent primers in, I don't think the spent primers won't matter since we use the H20 method with the fired primers intact, right?

 

[TackDriv3r]

That is what I do, and break them into 50 round "batches" based on the weight sort. Only a little time on my part.

I understand, but my matches requires 60 rounds for 3 matches for one event. May have to sort 100 pieces

 

[fkimble@charter.net]

two boxes of Lapua brass, both are the same lot number.

Those 200 pieces of brass with the same lot #? Isn't that by definition a 200 piece lot? I wonder what the plant calls a lot, a million or more? Wish I had a "lot" !

Frank

 

[jackieschmidt]

I have Lapua 220 Russian and 6BR brass that varies in several years of manufacture. I cannot tell them apart.

In 6BR, there is a slight difference in the neck wall thickness that came about when they dropped the old gold card board box for the blue plastic box.

The fact is, I have never paid any attention to the “lot numbers” of Lapua cases.

 

[Shurefire]

All of my Personal bests have been shot with unsorted, unweighed and untrimmed brass thrown from a cheap RCBS powder dispenser. But I admit the XTC target is more forgiving than others

 

[TackDriv3r]

I have Lapua 220 Russian and 6BR brass that varies in several years of manufacture. I cannot tell them apart.

In 6BR, there is a slight difference in the neck wall thickness that came about when they dropped the old gold card board box for the blue plastic box.

The fact is, I have never paid any attention to the “lot numbers” of Lapua cases.

Would you know if the " blue box " neck wall thickness is thinner than the old cardboard brass?

 

[Webster]

I recently bought two boxes of Lapua brass, both are the same lot number. Can I mix those two boxes of brass together and make it a 200 piece batch without it affecting accuracy at tournaments?

Both boxes were probably made from the same pile of brass at the factory. Maybe thousands of cases in a big pile gettig boxed.

 

[savageshooter86]

It’s the same lot
Number. Mix them all together

 

[Ned Ludd]

They're the same Lot#. You're not likely to get brass any more consistent than a single Lot# without adding sorting steps of some kind. If you're seriously worried that the brass in one box from a specific Lot# is somehow markedly different than the brass in another box with the exact same Lot#, I would suggest sorting all of the brass into 200 groups of one piece each. You won't get any better consistency than that.

 

[JFrank]

I do not mix them whether the same lot number or not. Each box is kept separate with neck thickness noted and reamer/barrel number and a couple other things.
Q) how many days do the machines run during a lot number and how many employees and shifts are running these machines ?

 

[searcher]

I do not know this for fact - but I assume a lot number is changed any time there is an adjustment to the equipment running the line or a change in the brass lot used to form the brass. From the beginning of a lot to the end of the lot run, there would be expected minor difference due to slight calibration changes due to wear, etc. I have measured a lot of Lapua brass, and I have only learned that the difference from one lot to another may not override the differences found within a given lot. So, I just weigh and measure all brass into lots - whether from the same lot or not. I have taken 1,000 Lake City once-fired cases of three or four production YEARS. After weight sorting into three groups, turning necks, pockets, flash holes, etc. - they shoot so well that I have not gotten better groups using Lapua 223 match brass that was not weight sorted or otherwise prepped for accuracy. That is not a knock on Lapua - just an illustration that there were certainly brass material changes made plenty of times, machinery adjustments - and running on different machines with that Lake City and sorting works. I'd not worry about mixing those boxes up - but I'd still sort them.

 

[jackieschmidt]

Would you know if the " blue box " neck wall thickness is thinner than the old cardboard brass?

All I know of is 220 Russian and 6BR.

When measuring with a Ball Micrometer, both are thinner by about .0005 when going from the earlier cases to the new.

I have three new boxes of Lapua 6BR that I am using in my no neck turn 6BRA, (.272 neck), and the neck wall is very consistent in thickness. Some of the best I have seen. The wall thickness is an average .0124.

 

[Joe Salty]

I myself want to try sorting by Velocity never mind weight volume and all the time wasted doing those thing.
I'd like to hear your thoughts!

Joe Salt

 

[JFrank]

I myself want to try sorting by Velocity never mind weight volume and all the time wasted doing those thing.
I'd like to hear your thoughts!

Joe Salt

I picked up that tip from @BartsBullets , a performance based , results driven exercise that’s easy to do.