Lc 5.56 brass vs commercial bass is Lc worth the extra

[Hypnogator]

Saw this thread Friday, so just for gits and shiggles, spent a rainy yesterday morning doing some weighing and measuring. From my reloading bench, I selected lots of 5 cases each of resized, trimmed and primed brass from Federal, PMC Bronze, PPU Match, and PMC X-Tac as well as 5 unfired primed Lake City 13 cases. First, I measured case capacity using some BLC(2) powder by filling the case to overflowing, then leveling the mouth with the edge of my scales powder pan. I poured each charge into the pan and weighed them with the following average weights (in grains):

Federal, 30.84, SD 0.30; PMC Bronze, 30.95, SD 0.37; PPU Match, 30.30, SD 0.31; PMC X-Tac, 30.19, SD 0.41; Lake City 30.16, SD 0.61.

Case weights: Federal, 96.12, SD 0.48; PMC Bronze, 96.46, SD 0.13; PPU Match, 98.17, SD 1.06; PMC X-Tac, 96.40, SD 0.49; Lake City 96.10*, SD 0.52. *Adjusted for weight difference of 0.2 gr. between CCI 400 and CCI 41 primers.

Case lengths: Federal, 1.7497", SD 0.0055; PMC Bronze, 1.7554", SD 0.0023; PPU Match, 1.7540", SD 0.0031; PMC X-Tac, 1.7540", SD 0.0022; Lake City, 1.7538; SD 0.0007.

Correlation of case weight to case capacity: Federal -0.51; PMC Bronze -0.06; PPU Match +0.44; PMC X-Tac -0.68, Lake City -0.42.

Bottom Line: Lake City cases don't have significantly less capacity than commercial cases, and there is no real correlation between case weight and capacity.

FWIW

 

[moxie]

Yup, what I've been saying all along. With very few minor exceptions, they're all the same.

Ain't no difference.

Mix 'em up & load 'em up!

 

[Walkalong]

Excellent job Hypnogator.

 

[moxie]

Agree. Thanks for the thorough job hypnogator.

 

[mboylan]

When it was available, the LC virgin brass (unfired, never loaded) from Midway and other sources was great. Priced right. Consistent. Centered flash holes. Less capacity than commercial but no biggie- I never loaded high enough charges to take note.

This link is to Midway: http://www.midwayusa.com/product/2317197849/lake-city-reloading-brass-556x45mm-nato-new-unfired
They've been out of stock over 18months.
Natchez has also been out of stock for a similar length of time I believe.

There is another place that has this in stock currently- the only caveat is that they don't guarantee all are from the same year. I no longer have this link as I recently cleaned up my bookmarks and decided my current inventory was enough. Maybe someone reading this can post it for him. Also, ensure your bolt action is stamped for 5.56. I personally wouldn't shoot 5.56 handloads out of a 223 rifle. If you're not loading to the higher end of published ranges it may not exceed the pressure limits of a 223 chamber, but how would you know what that charge is?

There is no dimensional difference between a case marked 223 and one marked 556. Most load data out there is 223 pressure. 556 pressure data used to be almost non-existent. That is changing.