Lake City .308 brass weight variance

AJC1 said:

Cool I just go on line and order 100 of those for my next match. Any suggestions on who has them in stock.

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It's PRICEY now days I'd simply MAKE MY own from LC cases from 50's-70's IF one can find the cases . IF not , Buy Norma or Belgian ,Swiss, German 7.62X51mm surplus ammo IF again You can find it . Before the Dipstick moved into DC it was all over the place Now harder to come by .

M852 Match Ammo in 7.62x51

$200.00

SELLER: Ronald Rehn Gunsmithing (FFL Dealer)

I kick myself every time I grab one of My 7.62X51mm Rifles gas and Bolt why you might ask . Well Years ago, actually decades ago I had the opportunity to acquire Several Cases of this and DIDN'T !. My only excuse was I was literally sleeping on a POWDER KEG at the time !.
Eventually one realizes you're out of Boxes ,buildings and SOME day you will MOVE and it MUST GO WITH YOU and You can afford only so many CONTAINERS . Anyway this is Sub MOA out of near anything which resembles a barrel ,some of the VERY BEST Contracted ammunition ever produced IMO . Sadly I've #6 boxes left out of #50 I did purchase .

I can't argue against sorting brass by weight because I have never done it. If I were to sort brass it wouldn't be by case weight but rather by water capacity. Lake City brass gives me excellent case life and I have worked up some very accurate loads using LC brass for my M1A. LC is my preferred 308 brass.

Scout21 said:

I intend to use the brass for hunting loads as well as some range use.

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No special treatment needed. Clean, size, trim, load.

GeoDudeFlorida said:

No special treatment needed. Clean, size, trim, load.

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I would agree, too. As I mentioned in my previous post, give the LC a try... all you can do is say 'Meh' and move on. I will say... if you work up a load with LC, and then you decide to switch to commercial brass, you will likely have to rework the load... because of the differences in case capacity. If you are in the node with LC, then switch, you may have to bump the charge up to get back into the node.

I have LC brass... it's not my favorite. Granted, I've had bad luck with my several attempts with it, but I think I'm the exception. I've pretty much sworn off it, but I still have about 1000 cases still in use... I'll use them until they fail, and be done with it.

Scout21 said:

I intend to use the brass for hunting loads as well as some range use.

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I'm sorry as I neglected to ask if you're using a Bolt or Gas gun ?. If you're using a Bolt rifle almost ANY good quality commercial case will give you more Ump . IF it's a gas platform then I prefer Rim strength of Military cases . I've got a substantial crushed pile of less than stellar commercial cases ,which have " Clipped Rim syndrome " and I'm most certainly Not over gassing the systems .
The One portion of the case's weak link is their base , as Nothing can be done with regards to softening or inducing ductility into them ,leastwise NOT SAFELY that I'm aware of . That's WHY I prefer Lapua ,Norma ,Belgian ,Swiss and German cases ,they simply HOLD UP ,just like the older LC cases . I'm one who thinks I'm being cheated if I don't get #20 reloads on a piece of brass As we all painfully know components are no longer cheap and brass is no exception .

Back to OP's original question. From a lot of LC brass, if the brass did vary a bit by weight, what would it matter, or how would the difference manifest itself?

Assuming a case is sized the same on the outside, it would seem a heavier case would have more brass somewhere internal to the case, which could cut down on internal volume, and perhaps change pressure, and perhaps velocity?

The difference in weight would not necessarily be internal. Some bench rest shooters check internal case capacity with water.

frogfurr said:

The difference in weight would not necessarily be internal. Some bench rest shooters check internal case capacity with water.

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Actually, that is what I meant. Internal case capacity. More weight = thicker brass. Perhaps case capacity smaller?

Anyway, I don't recall the weights, but did find new unfired LC brass to be slightly heavier than new unfired Starline. My response was to download otherwise similar LC brass by 1 grain of powder to account for it. It went bang and nothing blew up. From memory, can't remember what difference was in velocity, if any.

Garand's and M1A's are rough on brass. During ejection these rifles jerk and twist the brass (rotary bolt) while it is still tight in the chamber. Lake City hold's up to this better than other brass. I could see LC weighing a little more due to it's durability in the Garand's and M1A's.

I'm still convinced that older brass composition is slightly different ,than brass of today's manufacture . Good or bad ,it holds up better under gas gun tormenting ,at least in MY cases . It's every bit conceivable that older Military brass WASN'T ANNEALED AS OFTEN as Newer brass is during forming ?. I simply DON'T know for certain but given the circumstances with WAR and Production and NO one concerned with it's reload-ability it makes sense ,that the bases are Tougher after all it's where the cup is drawn from .

frogfurr said:

The difference in weight would not necessarily be internal. Some bench rest shooters check internal case capacity with water.

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BushMaster-15 said:

I'm still convinced that older brass composition is slightly different ,than brass of today's manufacture .

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I tend to agree... I don't think the brass alloy in cases today is as good as older brass, in both rifle and pistol... but the exact blend is likely different between manufacturer, between lots, between years, etc, etc. That's why while case weight may be different, case volume is the real determining factor.

Charlie98 said:

I tend to agree... I don't think the brass alloy in cases today is as good as older brass, in both rifle and pistol... but the exact blend is likely different between manufacturer, between lots, between years, etc, etc. That's why while case weight may be different, case volume is the real determining factor.

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I agree : Now take a cartridge case any caliber you choose , stop and consider the weight , OK . The cartridges in a given caliber are ALL the same size ( drawn to a specific set of dimensions and sized trimmed accordingly ) so when weight is considered the " EXTRA BRASS " must be in either the Base web and or in the wall thickness ?. Yet cup's are nearly all identical in size shape and to a lessor degree weight ,Right ?.
So IS THE DRAWING OF THE CASE WALL where the Excess brass is ?. Not necessarily and YOU or any of us can Prove it ,by a H2O volume test . Therefore in MY conclusion the excess is in the Web . Another interesting test is a balance point on cartridges ,like a 1"x 1/8" thick flat bar . Set on flat bar on edge take a handful of cases set one case on edge carefully mark where it balances ,then repeat with additional cases ;
DO THEY ALL BALANCE EXACTLY THE SAME SPOT . I think not . Measuring ID and OD for neck thickness and concentricity, is yet another clue .

Brass changes as it is fired. Case length increases, headspace to the shoulder changes, case head separation is possible due to the internal changing of the case. I don't think a simple weighing of each case is going to overcome all of that.

frogfurr said:

Brass changes as it is fired. Case length increases, headspace to the shoulder changes, case head separation is possible due to the internal changing of the case. I don't think a simple weighing of each case is going to overcome all of that.

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Correct can't change Brass working it expands and WE force it back ,can be minimized by minimal shoulder set back ,so as Not to over work it ,but the Neck will continue to flow forward ,hence why we trim .

I don't have a piece of flat bar in My loading room but do have and old Asus sound card out of a computer . So for giggles I balanced some cases LC 53 on it;s edge 0.0350" if you don't think that's hard try it . So as crudely as I could I measured deprimed annealed 7.62X51mm cases . From the Base upward 0.7030"- 0.7260" is where they balanced at . Trust Me and 1/8" edge is gonna be a whole lot EASIER
Tomorrow I'll go out and dig out a precision ground flat bar or My machinist square and do LC along with some other empties including commercial ,just to compare as they're ALL trimmed within 0.002" of each other . I'll run an H2O test on them as well .

A cases weight is only really viable when fully prepped. Case volume is only viable when fire formed in the same gun or after full prep. I made the mistake of testing both ways out of those conditions and got some garbage data... I've grown a little since.

Scout21 said:

I intend to use the brass for hunting loads as well as some range use.

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You could work with a smaller number of cases and a chronograph, those cases that display a large unexplained variation in fps when shooting the exact same load get set aside.
This is a performance based method of sorting brass without the uncertainty of volume or weight and how they correlate to point of impact.
I used to have hundreds of pieces of odd brass and now I just use a small box of good brass

frogfurr said:

The difference in weight would not necessarily be internal. Some bench rest shooters check internal case capacity with water.

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Case weight is a very rough indicator and case volume testing has its challenges and inconsistencies.

Charlie98 said:

I don't think the brass alloy in cases today is as good as older brass, in both rifle and pistol... but the exact blend is likely different between manufacturer, between lots, between years, etc, etc. That's why while case weight may be different, case volume is the real determining factor.

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What I have noted over the years comparing the new vs 40+ yr old brass. Is the older brass in general is much heavier. All toward max dimensions where today's modern it's as light as it can be saving on raw material. If you were to measure the wall thickness in the necks it quite evident. The old is running max where the new is barely meeting the min in some areas falling below.

A couple of grains difference in a large case may not be such a game changer. It does have a large affect on smaller cases. I had loaded some .223 RP cases and it was a super accurate. I then loaded some Federal cases (.223) and had over pressure problems. When I pulled the bullets and weighted both empty and deprimed cases the Federal cases weighed 11g more!

NO data will be collected for a few days ,as it's -22 Deg. currently and I'm not venturing outside to get into the container anytime soon !.

Now Federal and Winchester commercial .308 cases balance significantly closer to the base ,concluding there's more material towards the shoulder and neck than with MY LC cases . We also must remember capacity within a case with regards to H2O is meaningless ,when referencing powder charges. The density isn't comparable and powder weight with density is variable given powder choice Ball or Extruded .
I content therefore " POWDER CHARGE WEIGHT " is paramount regardless of cases used . Besides other than weighing cases and grouping said cases ,there's little to nothing which can be changed on them . Again conceding to Nature Boy's original advice ;

LOAD EM AND SHOOT EM The target is witness to whether or not any significant difference is present ,provided ALL other parameters are equally met .

You can weigh them out and take just those that fall within a parameter that you think would be good. Throughout the extreme flyers.

If you think weight variance is bad, just check neck runout. The majority will require neck trimming.

I've been through all this and have had acceptable results - not great, just acceptable. You can save yourself a lot of work by buying quality brass such as Hornady or Lapua. I've shot .243 varmint with Hornady for lots of years. If you want benchrest results, you really have to start with the capability of the rifle. While there have been great improvements in off-the-shelf hunting rifles, they just aren't going to those kinds of accuracy.

I use LC brass for all my 308 needs. I don’t sort at all. My 700 milspec will shoot it at MOA at 300 yards if I do my part. Supported position of course, with 168 SMK’s and IMR4895. Not match grade, but close enough for me.

What it really comes down to with regard to cases powder primers accuracy is ; WHAT the loads are intended for .
Example : I'm never gonna waste MY time weighing brass turning the necks inside and out aligning the base center with neck center precisely trimming flaring and adjusting bullets weight ,while loading MY ammo ,for a #80 year old DCM /CMP beater or M14 ,M1A .

If You're bench resting and have a $5-25K Rifle then YES absolutely but on the other hand , I'm Not taking that rifle hunting .

Other opinions will vary , Mine says 1.65"- .308 @ 100 Yd. is Minute of Hunting acceptable in My pocket guide .

Kill zone is 4" on deer sized animal and slightly larger up the chain , so IF You can hold free hand and strike fairly consistently within that zone , YOU are a GOOD Hunter . Truth be told I've used a lean too Rock tree bush or laid prone perhaps a total of a dozen times while hunting ,the rest off hand either scrambling up or falling down terrain and have only taken a knee twice while hunting ,mainly because of distance involved .
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