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Posted: 9/5/2011 5:50:36 PM EDT
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Okay Guys I have a question about internal brass capacity, for the past few years I have been using BH Match brass for my Savage .308 bolt gun that has had all the work done to prep it like primer pocket uniforming, flash hole uniforming and all trimmed to 2.007" and neck sized only until the bolt get's tight then I bump the shoulder back .002", I have the load worked out using 42.0g of RE-15 and it will do under a 1" grp at 100yrds if I do my part well the brass has reached it's life's end and the Mrs. gave me 200 Lapua cases to replace them, well my question is the BH Brass weighs in at 155g and the Lapua comes in at 175g and they are identical in size (2.007") well I filled each case to the top with RE-15 and the BH holds approx 2g more the the Lapua.
My question is do I reduce the load by 2g and come up or go all the way to the min and rework the load, will be using a SMK 168 (this is what I had been using) Thanks |
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To get true case capacity one should use H20. Weigh the fired cases and record, fill flush to top with H20 and weigh again. Subtract and that is your case capacity in grains of H20.
Your 42gr for the 168 SMK is not a max load according to Sierra. So IMO you could start right where you are at 42gr, but why? You are using different brass with different case capacity, if accuracy is your goal, then it's best to drop down and work up looking for a NEW magic load. You may end up right back where you started at 42gr, but then again you may not. You may find that there is a better load lower than 42 or a better load hotter than 42gr. I think you will like your new Lapua brass, great stuff! |
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Quoted:
To get true case capacity one should use H20. Weigh the fired cases and record, fill flush to top with H20 and weigh again. Subtract and that is your case capacity in grains of H20. Your 42gr for the 168 SMK is not a max load according to Sierra. So IMO you could start right where you are at 42gr, but why? You are using different brass with different case capacity, if accuracy is your goal, then it's best to drop down and work up looking for a NEW magic load. You may end up right back where you started at 42gr, but then again you may not. You may find that there is a better load lower than 42 or a better load hotter than 42gr. I think you will like your new Lapua brass, great stuff! I was thinking of going down to say 40g and working back up or should I go lower ? also I plan on following your suggestion on measuring with a fired case so I can start a log of internal case capacities of different brass. |
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See if this article helps. It also has links to the other articles in German's series on .308 loading.
http://riflemansjournal.blogspot.com/2011/01/cartridges-1000-yard-308-case-capacity.html Powder can vary for a few reasons, including humidity and batch variations. The best method to find the internal case volume is the water method and not assume using powder is the same. I would assume to drop at least the 2 gr and do the range work to see if you need to go up or down from there. Also, watch for the effects of the changes in the neck wall thickness and don't assume sizing will be the same between the two brands. If the wall thickness is much thicker, be sure to adjust your neck sizing technique to account for it. |
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BTW, I wish my Mrs. would give me brass when I needed it......... Sounds like you are a lucky guy! She actually has no interest in shooting but knows I do and know I really enjoy the reloading aspect of it so she says if we have the $$ just get it only problem is we don't have it .... 
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BTW, I wish my Mrs. would give me brass when I needed it......... Sounds like you are a lucky guy! She actually has no interest in shooting but knows I do and know I really enjoy the reloading aspect of it so she says if we have the $$ just get it only problem is we don't have it .... No worries! All the money in the world wouldn't replace your Mrs. |
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BTW, I wish my Mrs. would give me brass when I needed it......... Sounds like you are a lucky guy! She actually has no interest in shooting but knows I do and know I really enjoy the reloading aspect of it so she says if we have the $$ just get it only problem is we don't have it .... No worries! All the money in the world wouldn't replace your Mrs. I received my order from PD on 9MM 124's and the only thing she asked was "Why didn't you order more" God I love this woman !!! |
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BTW, I wish my Mrs. would give me brass when I needed it......... Sounds like you are a lucky guy! She actually has no interest in shooting but knows I do and know I really enjoy the reloading aspect of it so she says if we have the $$ just get it only problem is we don't have it .... No worries! All the money in the world wouldn't replace your Mrs. I received my order from PD on 9MM 124's and the only thing she asked was "Why didn't you order more" God I love this woman !!! Does she have a sister? |
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