LC brass year X vs. LC brass year X

[Fire Dog]

IN a custom 223 Match, bolt guns, Mixing years is suicide for accuracy, when looking for 3/8" groups and less.

Deburring the flash hole is another issue.

Checking for off-center flash holes is another issue; some years are just horrible.

Oh Man…! Off centre flash holes were a major source of pain in the Patootie for me and I used up all my spare de-priming pins for my RCBS die…
Range scavenged brass or mixed lots are worth just what you pay for them.
I hand de-prime any new military brass {sorts out any that have off center flash holes} then spin up a de-crimping RCBS case station tool head in a hand held electric screwdriver.
That brass now becomes “Who cares if I loose a case in the field” brass for my AR-180 coyote killer…
My bolt gun gets the Lapua…

 

[marchboom]

OK, sorted out LC 83, 84 and 85 brass. The average weights are (for 10 cases):
83 = 92.5 grs
84 = 92.9 grs
85 = 93.3 grs

Are these cases close enough to combine and expect decent load testing results?

 

[searcher]

I'd try to segregate by years if you have a large quantity to work with. If I end up with a batch that is of multiple years, I weight sort it, do a light turn on the necks and ream the flash holes. Doing these three things will go a long way towards making them uniform to one another. Because there will have been many batches of brass utilized between years (and likely during the same year), they will not all anneal the same and you will see differences in case stretch when shooting in an A/R, despite utilizing the same headspace and in annealing them all at the same settings. All that said, and despite the minute differences, once the brass is prepped as noted, it will shoot surprisingly well.

One thing about years that is readily evident just from looking at the brass is the difference in the way the primers are staked into the primer pocket. One year (years prior to around 2014?) will show a circle around the primer, while later years will show four or so "jab" marks around the primer. When handloading, I prefer the circular primer staking, though it depends on what your method of reaming or cutting the pocket prior to primer seating. Since I switched from a reamer to a cutter for the pocket work, I look at them equally. When using a reamer such as the Dillon or RCBS models, primer insertion can still occasionally be tricky. This is not noticeable when they are cut.

 

[ricco1949]

This is 20 VT load development with new barrel and 4000 rounds later after set back.....brass was LC mixed years but neck turned. 40 VM on top and 32 VM bottom.



I don't think year sorting would have done any better.....sure is GTG for PDn.

 

[jelenko]

OK, sorted out LC 83, 84 and 85 brass. The average weights are (for 10 cases):
83 = 92.5 grs
84 = 92.9 grs
85 = 93.3 grs

Are these cases close enough to combine and expect decent load testing results?

Probably. Some might say almost for sure.

Another way to test case capacity is to load up 3 rounds with cases from each year. Color each bullet with a different colored sharpie.
Then shoot them all to the same POA - a small dot on a white piece of paper. The sharpie color will leave enough color behind so you can identify which year the case was from.

If all shots have the same POI - you know it won't make a difference.

 

[ronemus]

"One piece could be made in January and the next made in December." Very good point and one that I have considered. Some LC head stamps look different even from the same year. So what am I supposed to think about that?

LC brass is formed and stored without a headstamp, which is applied in the loading process and may happen years later. There are changes in the contractor who runs the plant every decade or so, recently switching back and forth between Remington and Winchester; those changes are reflected in the brass. I group brass made by the same contractor irrespective of year, and sort by weight for my high-precision loads (1000 yd). I've long retired my LC brass after 12+ firings so I don't remember what years the transitions occurred, but that's public record. I'm now using a single lot of Winchester brass that I bought once fired my a Highpower competitor who bought it new - he bought primed brass in large lots, loaded them up and sold true once-fired brass to other competitors/

 

[ronemus]

OK, sorted out LC 83, 84 and 85 brass. The average weights are (for 10 cases):
83 = 92.5 grs
84 = 92.9 grs
85 = 93.3 grs

Are these cases close enough to combine and expect decent load testing results?

I have seen weight spreads as large as 5 gr within a single year. For precision work I group similar years (see above) and sort by weight.