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Old August 12, 2002, 10:49 AM   #1
Edward429451
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.308 Win Brass Cross Section

Awhile back I said I'd do this to compare brass construction and some expressed interest in seeing the results.

Well, I finally got off my kiester and did it.

What we have here is all once fired except the Lake City Match, which is twice fired.

(Finally found the macro switch on my borrowed cam, its a little flower icon.)

Left to right; Winchester, R-P, PMC, FC, LC Match.
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Old August 12, 2002, 11:37 AM   #2
C.R.Sam
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Thanks Edward.
Good for the doubters re the stoutness of LC and other mil spec brass.

Sam
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Old August 12, 2002, 10:33 PM   #3
Edward429451
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I went ahead and miked them in different places just to see how the numbers fell out. Interesting.

#1 Measurement is thickness of the sidewall at the top of Web.
#2 Measurement is thickness of the sidewall up away from Web.
#3 Measurement is thickness of the Web from inside primer pocket to top of Web inside case.

Winchester. #1-.048 #2-.041 #3-.066
R-P #1-.050 #2-.041 #3-.057
PMC #1-.073 #2-.045 #3-.080
FC #1-.050 #2-.045 #3-.073
LC Match #1-.051 #2-.042 #3-.073

So FC is on a par with LC Match. Winchester and R-P are on the thin side, and PMC is comparitivly built like a brick...

So Lake City brass is right up there with the best of them.
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Old August 13, 2002, 12:45 AM   #4
KP95DAO
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Case strength.

Thickness of the brass is not the sole determiant of its strength. The copper to zinc ratio and the hardness of the brass play a more important role.
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Old August 13, 2002, 08:43 AM   #5
Edward429451
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(Every time I get a theory goin, somebody a little better versed blows it out of the water!) (Thats good though, its one of the ways I learn)

OK, so whats the best brass to use? Or maybe a better question would be, what brass should I not waste my time on.

I have been using R-P brass alot, since I have so much of it, and it does seem to work well. But its the thinnest of the bunch, so I'm starting to think I should get away from using it so much.

I've always heard PMC brass was so good, but its significantly thicker than even the mil spec brass, (which is supposed to be reduced 2 full grains from max), so can I reasonably conclude that PMC brass should be reduced accordingly also?

(I can hear it now, try it and see, start low work up slow and watch carefully, right?!)

What about annealing the brass? When to do? After I first start seeing cracks at the mouth upon resizing?
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Old August 13, 2002, 11:25 AM   #6
KP95DAO
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Again; form follows function.

If accuracy if your goal, stay with the LC Match and the FC. The only thing I do to my LC Match brass is uniform the primer pockets. The FC brass I do that and turn the necks, slightly, plus reaming the flash holes.
The Rem is the worst in my opinion with Win not far behind. I have not worked with PMC enough to be able to offer an opinion.
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Old August 13, 2002, 01:31 PM   #7
Edward429451
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FC and LCM, kinda what I figured. I am going for accuracy. Thanks.
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Old August 13, 2002, 01:59 PM   #8
Steve Smith
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Of all the guys I know in the HP world, not one can say that there's a difference between LCM and LC except for the primer crimp. I certainly don't know, but I doubt that there's a difference myself.

Myself, I am doubting the necessity to weigh even my 600 yard cases. I have shot several matches this summer without getting to weigh my long range cases-wound up just digging into my pile 'o once fired. (Which for me is all LC, mixed lots, primer pcket squared,flash hole uniformed, trimmed, neck chamfered and deburred.) The only non-10 or X shots I had were due to stupidity, not the load or brass, that's for sure.
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Old August 13, 2002, 03:57 PM   #9
Edward429451
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I started to weigh my brass, but when I came up with up to a little more than a 5 grain difference in the first ten, and started thinking about segregating it into like weight lots, I figured it was more of a pain in the butt than it was worth and quit.

I'm not going for world championships, I just want to get better.
Weighing each charge is probably as far as I'll go to do that.
Maybe, just maybe, I'll start squaring pockets and uniforming flashholes. The brass I sectioned does look mighty un-uniform in those respects.
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