Re: Lake City Brass ?
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Shot In The Dark</div><div class="ubbcode-body">FYI, here’s some info I found elsewhere:
The military brass is harder for rapid extraction without breaking. Lake City is an ammunition facility owned by the government, but operated by contract. It was operated by Remington until 1984 or '85 and has been operated by Olin (Winchester) ever since. Federal is owned by ATK, an aerospace/defense munitions company, but is not connected to Lake City, AFIK.
Even if it were connected, that wouldn't matter. Lake City is huge. Something close to 500 buildings on over 3500 acres. It has all its own custom loading equipment, so what Winchester makes for its commercial brand has no relationship to what comes off the Lake City equipment. Indeed, the military requires some specifics, like drilled rather than punched flashholes, and no polishing after neck annealing that have no exact commercial equivalent.
As to quality, the construction is sound, but Lake City, like IMI, still has neck wall thickness runout and case-to-case weight variance that are greater than some commercial brass, especially Lapua and Norma from across the pond. My LC .30-06 cases typically have about 0.002" TIR (total indicated runout), which is not bad, though not as good as the <0.001" TIR that Norma and Lapua give me. Add to this that Lake City's drilled flashholes aren't always quite dead center in the cases I have, and you can't really call it match grade before selecting and prepping. Ironically, my LC Match cases are less consistent than what I've saved from LC ball ammo.
The next question will be where the brass comes from? If it is from disassembled surplus stock or new, unloaded stock, it is good. If it is once-fired from machine guns, their more generous chambers will tend to leave the brass long and thin at the pressure ring, so cashead separation tends to happen more easily in reloads. If it was fired in an AR and is going to be used in another AR, especially one with a NATO chamber, it should be OK. Just clean it, if that hasn't already been done, and anneal the necks once before your first resizing. Using another fired case from your gun as a reference, only size them enough to push the shoulders back about 0.002" from your chamber's fireformed brass shoulder length. That will minimize the chance of head separation.
Remember the lower case capacity. You will have to reduce your commercial brass loads and work them back up with this stuff, watching for pressure signs. Your velocity at a given maximum pressure will be slightly lower than with, say, commercial Winchester, because the lower capacity reduces the peak pressure charge, and the reduced charge can't make the same volume of gas to push the bullet. For example: In .308 Winchester a 54,000 PSI load of IMR 4895 in a Winchester case will drive the 175 grain Sierra MatchKing about 50 fps faster than a 54,000 PSI load of IMR 4895 in a Lake City case will do. That is because the Winchester case needs 1.9 grains more powder to get to that same pressure, and the extra gas from that keeps the pressure curve from falling as fast, so accelerating pressure stays a little higher beyond the pressure peak. That isn't enough difference to matter at anything except ranges from about 500 to 1200 yards.
Another source:
Thanks for the link on the .223. The weight extreme spreads are interesting, and Lake City is certainly above average. Winchester's wide extreme spread is typical for them. Theirs is quite wide in .308, too. They need to make a play date with the W. Edwards Demming Institute.
The LC and other military brass tends to be a bit harder, which is good for automatic extraction in the gas guns. Remington and a lot of other commercial brass has always been of similar weight to the military. As you've observed, some brands are even heavier.
The one that stands out as being lighter in larger calibers is Winchester. In 1992, the U.S. hosted the Palma match, which is international the participating countries take turns hosting. The Palma is a long range match (800, 900, and 1000 yards) fired with 7.62x51 or .308 match ammunition, and takes place every three or four years, depending on what the international Palma committee decides. The host country provides the ammunition for the event. Under the rules in effect at the time, the bullet could not exceed 155 grains, ando some countries provided anywhere from 143 grains to 155 grain bullets. The host country has to supply 10,000 rounds to each guest country for practice during the two years before the match, so everyone gets an equal opportunity to find their zeros and get used to how the wind blows the bullets around. The brass was military match standard at the time.
For 1992, the U.S. decided to provide the best Palma ammunition ever assembled. Middleton Thompkins and others who help find sponsors for the U.S. team, talked Sierra into designing a maximum weight MatchKing that would stay solidly supersonic to 1000 yards out of the long Palma gun barrels. Some past ammo had been pretty marginal in that regard. They also talked Winchester into designing a special .308 case with maximum powder capacity for this heavier bullet. Winchester did that by forming a semi-balloon head case, with brass recessed around the flashhole, leaving just enough for the primer pocket to be properly formed, and creating an extra 5% powder capacity.
The loads were developed and the ammunition was loaded by a small outfit on Dillon machines. I've forgotten who it was, but saw an article on the adventure once, long ago? In any event, it was a big success among the Palma shooters. The extra 75 fps the extra powder space makes possible is not necessary for people shooting service rifle matches, but when you are trying to stay not only supersonic, but preferably above transonic velocities to 1000 yards, every little bit helps.
The ammunition worked so much better than a lot of past Palma ammo, that the rules were changed after '92 to require 155 grains bullets. That put Sierra in the cat seat for long time, though I've noticed Lapua now has a 155 grain Scenar that has better B.C.'s claimed than the Sierra design. No doubt, that is just to be considered for Palma ammunition.
Winchester, meanwhile, got so many requests for the Palma cases that they switched their standard .308 cases over to the semi-balloon head design. If you now look down in other larger Winchester rifle cases, you find that recess in many of them. Where current Lapua production .308 brass weighs about 172 grains, and Lake City Match weighs about 179 grains, the Winchester weighs 157. Cartridge brass weighs 8.53 times the weight of water, so, assuming uniform exterior dimensions, you gain a grain of water capacity for each 8.53 grains of brass weight reduction. A lot of stick powders have bulk density on the order of 0.85 times that of water so, roughly speaking, you gain a grain of powder capacity for every 10 grains of brass weight reduction. I expect Winchester concluded the brass reduction didn't hurt their costs, either.
The .223 seems to be one of the exceptions. Winchester and Lake City weigh about the same, among what I have, same as the chart on your link shows. So, you just have to look. I have no idea why the South Africans (PMP) put so much more brass in their cases?
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Great info...I just found 700 pieces of LC 89 Match brass and was wondering what to do with it. I also have a couple thousand pieces of Black Hills .223 Match brass...has anyone had any experience with BHA Match?
