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Old August 8, 2009, 08:35 AM   #1
bgdv1
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Loading military brass question

when loading for my 308 i use winchester brass. ive come across some military brass and was planning on reloading some of it. my question is do i have to reduce the charge amount for the military brass being it is thicker brass ? or am i wrong and stick with my current charge of 42 gr of imr4895 w/168gr hornady amax bullet.
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Old August 8, 2009, 08:56 AM   #2
Slamfire
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It used to be that military brass was much heavier than commerical. My 70's vintage LC 308 weighs around 177 grs a case. Period Federal Gold Medal match varied from 155 grains to 168 grains. I picked up some modern Federal and the weight was up in the 170's.

I have shot thousands of 168 SMK/nosler/hornady match with 41.0 or 41.5 grs IMR 4895 LC WLR/CCI#34. I am not shooting max loads either. Mine are good loads that I can shoot in 100 F weather and not have leaking primers.

42 grs is a little hotter than my loads.
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Old August 8, 2009, 09:16 AM   #3
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Current Winchester .308 case production uses the semi-ballon head design they developed for the 1992 Palma match ammunition. It weighs about 155 grains and has slightly over three grains more water capacity than the 186 grain IMI Match .308 cases I have, and almost three grains more than the 180 grain LC Match cases I have. I don't have any current production ATK (Federal) managed LC or FC military brass to compare.

If you're loading to 2.800" COL, you're 42 grain load is not maximum for a Winchester case, which the Hodgdon web site puts at 45 grains, and should not exceed maximum pressure even if used in the military case. But if you have a sweet spot load for accuracy at 42 grains in the Winchester case, and want to match the barrel time you are getting from it in the military cases, QuickLOAD estimates it would be 40.4 grains for cases in the 180-186 grain range, and 40.9 grains for cases in the 167-173 grain case weight range. These won't be exact because some portion of the weight difference is due to external dimension variance within tolerances, so you may still have to tweak up and down a few tenths of a grain.
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Old August 8, 2009, 10:09 AM   #4
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Sorry for changing the direction but a question to Unclenick

QuickLOAD estimates
I had never heard of quickload before and looked it up. Seems like a good software package,,, do you like it?
Thanks
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Old August 8, 2009, 10:39 AM   #5
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I've come to depend on it. It is highly flexible, so there is a learning curve, but it does a very good job in most instances if you get all the correct details entered. I like to cross-check it by running it against load manual velocity and pressure data. The match is seldom exact, but often surprisingly close, and you learn how to adjust it to match. You also quickly learn how different factors affect load performance; case capacity, bullet seating depth, bore dimensions, barrel length, lot-to-lot powder burn rate variance, etc.

I look at it this way: the manuals supply real firing data, but in guns that don't exactly match what I actually have. The software lets me match the gun to exactly actually have, but is mathematical firing data. Between the two, you can usually get a very good idea of what is happening in your gun verses the test gun used. If you have a good quality chronograph, you can tweak powder burn rate to get a powder model that matches your purchased lot as opposed to just what's in the database. Chris Long's site has some information on working with that.

The program now comes with two external ballistics programs, QuickTARGET and QuickTARGET Unlimited. The former is a straightforward and fairly easy to use external ballistics program that imports results from QuickLOAD directly and employs the usual published G1 ballistic coefficients to work out trajectory tables. The latter is a more complicated but more flexible program that lets you work with all the different BRL drag functions and their ballistic coefficients.

All three programs export data to Excel files (if you have Excel) for doing your own graphing, which lets you combine as many sets of data as you like.
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Old August 8, 2009, 10:51 AM   #6
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Thank you Unclenick.
I will be ordering one very soon.
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Old August 8, 2009, 05:40 PM   #7
bgdv1
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thanks for the reply's i may load some at 41 gr and compair loads and some at 42 gr and see how they work, thanks again.
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