What's us with quality control of Lake City 223 brass/ trimming a five gallon bucket of processed brass/ notice when trimming at 1.75 that some was short at 1.731 and some neededcalot of trimming/ took a hand full and measured them/ 1.731 to a maximum of 1.792/ to me that's a big difference/ anyone else notice this

Does a machine gun or an M4 really give a damn?

Unless the the brass derives from a single chamber I'd draw no conclusion from that length variation.

My thoughts as well.

Even if it does I have never seen each and every piece of brass from Lapua, Nosler, Norma, Federal, Remington or Winchester blow out to the exact same length on first firing.

This is true, but a matter of degree. OP describes a variance of 61 thou. I'll occasionally see as much as 6 thou difference in stretch in a batch of 7.62 or even .375s - one headstamp, fired in one chamber. Multiple brands would increase that variance, sure.

Which brings up another issue. Metal to be trimmed comes from somewhere. I sometimes use bulk 7.62 brass. But step one is to run every piece into a Wilson case gauge. Can do this while watching a movie. By feel.
Cases noticeably stretched get culled. Right then and there. Cuz I don't need to waste time, sizing die life, and lube to discover cases that a) might still be hard to chamber, b) will require more trimming than most of the rest and, c) are destined for a partial case separation. Those culled cases were overstretched on first firing. M240 chamber? Whatever. I don't need the aggravation. Just part of the economics of bulk brass.

I'd take the same approach with 5.56. If I weren't so lazy.......I just shoot factory in 5.56.

I have buckets full of military brass, 223, 308, & 30-06.
Military brass is a lot of work. I use the 30-06 military brass only for cast loads anymore. I now have enough ‘factory’ brass for the 308 & 30-06 that I don’t use the military brass for hunting anyway. But 223 - I’ll load up more than a thousand 223 loads for a PD shoot some times.

Military brass is cheap. But like I said a lot of work. One thing I do with any new to me brass is to trim it to length. I’ve also been known to measure neck thickness to be sure one side isn’t thicker than the other, measure the flash hole to be sure it’s centered, and weighed the brass throwing away brass that varies to much in any area.
I’m glad I did that when I was younger. I don’t think I’d do that again.

As I recall military brass isn’t pristine, even the ‘match’ military. But it is cheaper than Nosler brass.

Small base dies from RCBS in 308, 06 and 223, seems to bump things back into more consistency, when I first size the brass.... Most of what I have for brass is just range pick up brass, and there is always tons of it laying on the ground at our local range... one thing ya gotta love about those Californians.. use our range, and just leave their brass laying all over the ground.... as I've heard all too many times from them... "Who cares! Its Oregon!"

Since Winchester got the contract I wonder if the quality is still held to the same guidelines.

I like Lake City brass and I am willing to work it until it fits my needs. I have noticed that the lengths vary, sometimes by a large amount just like Stevered describes. I do sort mine by length. The short stuff goes into my bolt actions (1.754 and shorter) and the longer stuff I use for semi automatics. The longest I trim is to 1.765. But most of it falls into the 17.55 and 1.760 range. Yes, this means measuring it with a set of calipers and bagging the different lengths and trimming it to the length I want. But, it's good brass and it's worth the extra work.

kwg

I trim every piece, learned the hard way like I do everything else

I must be living right...
I trim Lake City Brass and other brands, after I've had 10 to 15 reloads on them.
Back off the gas pedal on the powder charges just a hair or so.

50 plus reloads out of a batch of 223 and a lot of other cartridges I shoot is nothing out of the ordinary.
a little prudence on the reload bench, and annealing often works wonders...

between that and range pick up brass, I really don't have a big investment in the brass dept.

Ya learn some secrets to take care of it, it'll last a long long time.

Yesterday evening and later this morning, I'll be over at the range, ringing steel at 300 and 400 yds, with a 6 x 45, and an 80 gr SP, pushed along by Small Pistol Winchester Primers and 10 grains of Unique. Just practice, but that kind of service, that brass will last for a 100 plus firings...

I use to learn everything the hard way, just like Hanco above. But I learned to pay attention and apply what I learned on top of that...hence how I've learned to stretch out components life span.

All this brass was fired out of the same gun/ not a machine gun or an M4/ all factory ammo/ that's why I say the Lake City must have QC issues/ brass length from 1.731 to 1.792 is a big difference for once fired brass.

That's excessive. What year on headstamp?

2021/ newer batch

What was the difference before firing?

Wasn't my ammo I have no idea

👍🏿👍🏿

I run all of mine through small base dies, ream out the primer crimp, trim to trim length because I’m loading for two Rock River AR’s.

What difference does the length make when you get it make as long as it still holds the bullets? If it’s a touch short, does it hurt anything? I’ve used a ton, because my boys best friend brings us Lake City when he comes home. I’ve never seen any shorter than trim length.

I'd want to know, too. Where is the trimmed material coming from? Excess neck lengths of unfired rounds? Short case necks are not a big deal. 32 thou over max length might be.

Or is it base to datum stretch? I'd plunk a sample of unfired ammo in the case gauge.

You would think cases that are in the 1.790 + length would be into the lands/ raising pressures

Unless the pre-fired case length wasn't into the lands. If the base to datum line dimension is very short the stretch will occur on firing. Fired case length before sizing will probably be OK.

Case gauging/case length measurements of both unfired rounds and un-sized fired cases would help sort things out.

If this is range pick up stuff
It could be reman
I know black hills used to load LC brass as reman ammo and was some cheaper than new stuff

I don't think anyone has mentioned it yet, but those would be manufactured since Winchester took over the
Arsenal from Federal. Don't know if that matters or not, you'd think the feds would have the same quality requirements no matter who is the contractor. Personally I have only found a few 21 - 23 dated cases when I have cleaned up after myself at the range, I'm saving them back to test separately when I get 20 or so. Everything gets checked every loading for length and trimmed if necessary anyway. I've always found LC to be good brass after the initial prep and well worth the effort. As always YMMV.

I get a lot of mileage out of Lake City brass....a lot of it with over 40 reloads and counting...

I usually am not pushing its pressures to the extreme... and I use it in bolt actions... single shooting it..

I recently picked up 250 pieces of this same brass from a local guy who doesn't reload. I have found the same variances. Made me wonder about QC on the Winchester run lines, too.

I'm going to FL size them, trim them to a consistent length and shoot them.

Ed

The 223 LC stamped brass is shorter than the standard LC w/date brass.

There like Federal brass

I don't think this is super common, but there are AR "builders" out there who put together barrels without the proper gauges. I would think excess headspace would cause the "datum stretch" you referred to. Brass case length of 1.790" would make me do some measurements and I don't think I would bother with trying to use casings where the shoulder had moved .020" or so. Could end up with casehead separation.