OK to mix different lots of Lapua brass?

[Bayou]

I keep brass segregated by # of times fired so I can anneal after every fourth firing. Right now I have 50 pieces of once fired from two different lots. I want to mix them together so I only have to do one tumbling run. I use a rotary tumbler with aqueous detergent and SS media and usually tumble for 4 hours. So an extra tumbling run to keep these two batches of cases separate is sort of a big deal. I weighed a bunch of cases from each lot when I first got them and there was no difference between them. So I was thinking that if I mix them and then segregate them by weight for individual strings I'll be fine. But before I do that I wanted to ask this question in case there are reasons for not doing this that I'm unaware of. Thanks!

EDIT: Forgot to mention these are 308 cases for a bolt gun.

 

[Greg Langelius *]

Re: OK to mix different lots of Lapua brass?

I segregate my brass from first firing to last. The COF I practice is 40rd for score plus unlimited sighters, so I tend to do my handloading in batches of 50. I keep the ammo in 50rd pistol ammo carriers and those inside ziplocks. Since I single feed by hand and have disabled my ejector, keeping all the brass together is rather easier.

I suppose, especially for semiautos, that combining different lots of same-brand/chambering brass is OK, especially if it's done prior to brass prep.

The final step of my prep is fireforming followed by individual weighing; to segregate the brass into lots by most similar weights. I don't put a lot of credence into the value of weighing brass, as its relation to individual case volume is not that consistent, but weighing probably better than not.

Greg

 

[turbo54]

Re: OK to mix different lots of Lapua brass?

I'd mix them and never think twice about it.

Before I was fairly meticulous about keeping brass sorted, I had 3 or 4 different lots of Lapua brass, each of which had been fired 2, 3 or 4 times and had been through a couple different rifles.

When I decided to be more careful about segregation, I FLS'd them all, trimmed to a common length, annealed necks, and dumped them all in the same bag labled "multiple firings". Last time I loaded them up I was getting 4" groups at 600 yards.

 

[Leaddog]

Re: OK to mix different lots of Lapua brass?

I don't worry about it too much. I'll keep my first 2 or 3 firings segregated, but after that, they go into the 3+ firings bin.

If you are sorting, it doesn't do too much good to weigh the case only as case heads will vary in weight. You should weigh case capacity by filing with alcohol(91% or higher). Water has air in it and does not give consistent weights. Weigh the empty case, fill with alcohol to the case mouth rim, and weigh again. Subtract difference. Sort your brass by this method.

Unless you are shooting competitvely at 600 yards to 1000 yards, I would just skip this step and go out and shoot more. Good luck.

 

[Greg Langelius *]

Re: OK to mix different lots of Lapua brass?

These are all good suggestions.

I like to keep my brass lots segregated because I beleive that neck hardening alters neck tension, and keeping the batches together lets them all harden fairly equally within a given batch.

If I wanted to measure volume, I'd measure volume, not weight. I like a dry medium, like the powder I'll be loading with, or maybe even walnut polishing medium, for filling the case and measuring. I think wet media has issues like surface tension and wetting that simply don't occur with a dry medium.

Greg

 

[turbo54]

Re: OK to mix different lots of Lapua brass?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">These are all good suggestions.

I like to keep my brass lots segregated because I beleive that neck hardening alters neck tension, and keeping the batches together lets them all harden fairly equally within a given batch.

If I wanted to measure volume, I'd measure volume, not weight. I like a dry medium, like the powder I'll be loading with, or maybe even walnut polishing medium, for filling the case and measuring. I think wet media has issues like surface tension and wetting that simply don't occur with a dry medium.

Greg </div></div>

Greg, I've ever "tested" case capacity with the powder I intend to load with, but have found this varies ~2gr, at least with Varget, H4350, H4831sc and RL15 in a 308 or 284 case. It really matters how much you tamp the powder to settle it. I have found this to be useful in discerning how much powder (max) can realistically fit in a case, but question it's usefulness in comparing case capacity across a batch of cases - where capacity might only vary 1/2gr from one to the next.

 

[Greg Langelius *]

Re: OK to mix different lots of Lapua brass?

Good to know. When I did mine, I used a drop tube to overcharge the cases and weighed what did not fall aside. But for these and the other reasons I stated, I tend not to put a lot of credence into the value of individual case capacities.

From a philosphical viewpoint, if I were to do so; I would also be constrained to do a lot of other handloading micromanagement tasks that I basically loathe doing, just to give the practice(s?) justifiable meaning. I'd really rather not.

Instead, I minimize the steps I do take, and put my primary attention into doing that few with best diligence. Reaming flash holes and weighing charges tend to be my salient issues.

Greg