Lake City 5.56 Brass Reloading

[GWV]

Can brass with different year head stamps be be mixed together in one group to reload. It is LC brass so why should the date it was made matter?

 

[jasophil1]

Hey there made stored year stamped when loaded I have been told check the weight.

 

[PigButtons]

Take some detailed measurements and you will soon see why, even same year with slightly different head stamps will differ by a significant amount. Weighing is a good start but I went to 4x magnifiers to differentiate the different 2011 head stamps for example. On one batch the two digits of the 11 were spaced at 90* the other they were much more like 60*. Maybe better eyes would make it easier to distinguish but at 67 I need more help. There was a 3gn difference in weight and since the outer dimensions can't change much that means that the case capacity must differ due to thicker walls or case head.

In the long run I guess it depends on what you are trying to accomplish; if MOA is all you are after you may not need to be so particular.

 

[JB10]

I never sort them. I just prep them all and load. I use them in a bolt rifle with very good accuracy. Best part is they were free. I have had same good luck with federal brass. Im not looking for bench rest accuracy but my loads are under 1/2 inch at100 yards.

 

[std7mag]

Different lots are different, or have the potential to be different.
Get a different lot & your internal volume can change, changing your pressures.

While i was shooting pick up range brass, i sorted by weight. Hey, like was said, they were free.

I'm now shooting Starline 5.56 brass exclusively.

 

[Uncle Ed]

How to Prep Mil-Surp 5.56 Lake City Brass — Save Money​

http://bulletin.accurateshooter.com/2021/06/how-to-prep-mil-surp-5-56-lake-city-brass-save-money/

Accuracy Potential of Mil-Surp 5.56×45 Brass​

So, how accurate can previously-fired GI surplus brass be in a good National Match AR-15? Well, here’s a data point from many years ago that might be of interest. A High Power shooter who wrote for the late Precision Shooting magazine took a Bill Wylde-built AR match rifle to a registered Benchrest match. His first 5-round group ever fired in a BR match was officially measured at 0.231″ at 200 hundred yards. This was fired in front of witnesses, while using a moving target backer that confirmed all five rounds were fired.

He recounted that his ammo was loaded progressively with factory 52gr match bullets and a spherical powder using mixed years of LC brass with no special preparation whatsoever. Obviously, this was “exceptional”. However, he had no difficulty obtaining consistent 0.5-0.6 MOA accuracy at 200 yards using LC brass and a generic “practice” load that was not tuned to his rifle.

 

[jelenko]

On the 'generic' practice load.
Let's remember that in service rifle competition, everyone uses a 20" barrel. There are a bunch of loads [bullets/powder] that have been developed over time for these rifles. Think of all the effort the Marine and Army marksmanship teams put into finding loads that work across all their rifles. So, it's not surprising that a 'generic' load produces .5 to .6 MOA groups in an ar15 with a match grade barrel.

 

[Coyotefurharvester]

For hunting or shooting where brass recovery may not be possible, just load and shoot.

 

[TheOtherZilla]

In my AR's it's load and shoot. Bolt guns, I am more picky. Usually use Lapua, or another brand brass all the same.

 

[MGYSGT]

The only thing I do with plinking ammo is small base resize the first time I use it. Other than that ream out the primer pocket and load. Forgot one other thing. Trim to length.

 

[searcher]

Can brass with different year head stamps be be mixed together in one group to reload. It is LC brass so why should the date it was made matter?

Any time a piece of brass is made a tiny bit differently (either because of tooling or a batch of raw product is different) the shooting characteristics of the finished product can vary a bit. I found that when I use LC .556 brass, (or other military brass I have used such as Winchester), I need to reduce my load by an average of 3/10 of a grain to match the same velocity with a given bullet, primer and powder - as opposed to using commercial brass, of which I normally use Nosler, Winchester, Remington and Lapua. I have never run into variations in LC brass (despite any extreme weight differences between lots) that created a need to change the powder by more than 3/10 or so of a grain to arrive at the same velocity between the lots of LC brass. This would tell me that I can load all mixed LC brass and, as long as it is charged 3/10th of a grain under the same load I'd use in commercial brass, It will be O.K. in respect to pressure, assuming the commercial load was not an unsafe load. The 3/10th grain variation within the LC brass (or LC versus commercial) usually equated to an approximate 30 fps to 45 fps difference when shot over a chrono. So - if you find an accuracy node that is very wide with a particular powder and bullet, the velocity spread may not even affect the accuracy as much as you might think. My own personal experience is that the differences between neck tension will actually make a bigger difference in accuracy than the brass weight differences. As such, turning the necks on your "mixed' brass to a uniform thickness will help to make them all shoot better as a group, though may defeat the purpose of mixing them together - if not wanting to weigh them. If you don't want to separate just because you don't have enough of each lot - turning necks is a great trick to make a bunch of odd lots work together better. So the short answer is - yes - mix them up if you want. For extreme accuracy, I'd sort by year, then weight and turn necks. For blasting - just load them all at least 1/2 grain below a commercial brass load that is at least 1 1/2 grains below the max - and you are good to go. I'd still work up from a lower load. Good luck!

 

[Ned Ludd]

Lot-to-Lot variance is the potential issue. Your precision requirements will have a big impact on whether mixing the brass is a good idea. If you want the best possible precision, it's better to keep the Lots separate. If you simply want some decent plinking ammo, I doubt you'll notice the difference.

A simple way to test would be to load up enough rounds of each year head stamp (separately) with the exact same load, then shoot a few groups with each for comparison and determine average velocity. That will tell you pretty much everything you need to know about whether the two Lots behave the same. Alternatively, you can simply weigh 10 or so empty cases of each to determine whether the weights are pretty close between the two different headstamps. The greater the weight variance between the two, the greater the internal volume variance will likely be. In fact, I would do the weight test first, regardless of whether I did the head-to-head precision/velocity test afterward, just because it would only take a few minutes. However, the precision test is not too difficult and will be the ultimate arbiter of whether mixing the two Lots will work for your needs.

 

[butchlambert]

I was given 8,000 rounds of LC brass of different years. Visited with a friend that has won a lot at Camp Perry and owns one of the most reputable AR companies. John said it is a waste of time to segregate the LC brass.

 

[riflewoman]

A couple of thoughts.
First Lake City 5.56mm brass is made on SCAMP machines. These are high volume production machines that have 24 stations each piece of brass starts out as a cup and comes off as a completed case ready to load. There are dots in the case that code which station it was processed for all operations.
A SCAMP machine has multiple turrets of tools and the tools are changed when parts are measured out of spec. After all the cases are run on this machine, they get dumped into one big bin and off they go to loading packing and assembly. You could, I suppose, sort cases by “Dot code” previously mentioned, but there’s no guarantee that the third draw die for station 4 wasnt changed from one day to the next. So the third draw die in station 4 that was removed, then repaired might get put into station 13. When the year changes, the bunting die changes the numbers for all stations, that is all.

second, so with all that, it’s a waste of time.