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Old December 16, 2010, 12:49 PM   #1
Bill Daniel
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Newberry's OCW- Question

Does the brass matter? I need 27 loads to complete my initial load development for my 308. I have plenty of Lake City brass already primed and prepped. Can I use this to establish my optimal charge weight even though I will use Lapua for my actual target load? I can use a mix of Hornady and Lapua but do not have enough Lapua for this 27 number. If it matters significantly I can fire form another 10 or so Lapua cases.
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Old December 16, 2010, 01:42 PM   #2
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It's been some time since I read that process but if memory serves, he used mixed brass.
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Old December 16, 2010, 01:51 PM   #3
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Makers use different thickness brass and the cases have different internal dimensions. So if you work up a load based upon one case that load will not work in another. They will be close. You could sort the brass by case water volume.
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Old December 16, 2010, 01:52 PM   #4
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I don't recall seeing anywhere that he references what brass he uses. His instruction page is found here.

However, just going by what I know about the process, I would imagine that using mixed brass would not be the best idea. If the volume is close to the same then you shouldn't have any trouble but if the case volumes vary by much then you'll be developing different pressures, possibly effecting how well the powder burns and definitely effecting the muzzle velocity.

Whether or not it would be enough to matter, I have no idea. Probably, in a bench rest quality gun with a bench rest quality shooter, it would matter. For me, I would guess I couldn't tell. For you...?
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Old December 16, 2010, 03:14 PM   #5
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Newberry's system applies to all brass, individually, but not to mixed brass for a given load. Especially not in .308 and .300 WM where the different case brands have a lot of capacity difference.

You'll see his preference on his recipe page. It is all Winchester brass. No other. Winchester .308 brass (avg. wt. 156 grains for the last 1000 I got) has about 1.9 grains more water capacity than Lapua (avg. wt. 172.5 grains for my lot), and Lapua has about 0.8 grains more water capacity than Lake City (avg. wt. 179.5 grains; I have examples from 177 to 182 grains, depending on year and whether it is match or NATO).

That's just too much change to expect a tuned load to carry over. Lapua will want about 1.2% more powder than Lake City, while Winchester will want about 2.7% more powder than Lapua to get a matching barrel time. These are figured for Varget under a 175 grain SMK, but even though these ratios are rough for other powder and bullet combinations, they will be close enough across the board to save you having to fire as many rounds in new round robins when you change brass, knowing roughly where you will land.

Keep in mind that case capacity is not the only factor. Neck tension differences from different neck hardness will have an effect, too. Other things that will make you refire are: different lengths and jacket thicknesses on different brands of same-weight bullets, different primer brands, different COL's. Just as you have to knock loads down and work back up with any component change, the same will happen to Newberry loads.
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Last edited by Unclenick; December 17, 2010 at 08:38 PM.
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Old December 16, 2010, 03:28 PM   #6
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I stand corrected. It must of been some other load developement process where I read that. I would like to retract my previous statement.
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Old December 16, 2010, 10:09 PM   #7
res45
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This might be where your read that,he did use different brass mfg. with his OCW load. Although he did mention his preference for Win. brass also

http://optimalchargeweight.embarqspa...ple/4529811475
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Old December 17, 2010, 12:29 AM   #8
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I thought I'd read it there. Thank you res45. I would like to retract my retraction and refer back to my original post.
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Old December 17, 2010, 08:37 AM   #9
Bill Daniel
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Newberry OCW-Question

Thanks fellows! I think I will fire form some more Lapua and keep every thing uniform (same brass, bullet, primer and oal) for this target load development. The great thing about this hobby is never having to worry that you know it all or have perfected anything beyond improvement.
Thanks, Bill Daniel
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Old December 17, 2010, 09:01 PM   #10
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Let me restate what I don't think I communciated very clearly before: There is no guarantee of these loads working with mixed brass. Newberry looks for equal performance charge spans of at least 0.6 grains with his loads, and if you are shooting .223 Rem or some other round for which all brands of brass tend to have close or similar capacity, you may be just fine with one charge weight. But for .308 Winchester, the differences between brands are too great. You would need over 2.5 grains of Varget going from Lake City to Winchester to keep the same barrel time in the load I was looking at. That's way beyond the charge spans Newberry expects to achieve. Going from Lake City to Lapua .308 brass with the Varget load takes about 0.6 grains, so if I loaded at the high end of what I found with Lake City, the Lapua would just barely fall in with that same load being the low end of the span you would find developing the load in the Lapua cases. So the load might look good for both, but it won't leave much room for powder dispenser error. And it still won't hold up in Winchester.

You could get lucky and find something that works over a wider range than 0.6 grains. Hatcher tells of a coarse grain powder similar to IMR4320 that his arsenal loading equipment could only throw within an extreme spread of 1.7 grains for .30-06. Yet the ammunition loaded with it outperformed other, finer grain powders that could be thrown to within 0.6 grains on the same equipment. The coarse stuff wound up being the load for National Match ammunition the year he discovered it, and was used to set several records.

Good luck with it.
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Old December 17, 2010, 09:07 PM   #11
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There is no load that can ignore different/mixed cases, bullets, etc. Therefore no load development method can ignore them. Well, not if we want to achieve much accuracy.
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Old January 25, 2012, 12:02 PM   #12
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some brass can expand or contract differently, which will give different pressures. long story short if you want to make accurate loads stick with the same brass. i have Winchester and Remington brass.i usually will make one box Remington brass and another box Winchester brass.keep it consistent and keep it simple.
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Old January 25, 2012, 01:40 PM   #13
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Once you do an OCW workup for each brand of brass you'll find out whether or not you can mix brands interchangeably.

Believe it or not I get very good performance from the same charge of 4064 in Lake City brass as I do in Winchester brass, no need to rezero the rifle. Of course 4064 is a "slow" powder for 308 and so it isn't totally burnt before the bullet is moving down the bore and increasing the effective chamber volume. Your experience with a different powder (or different brands of brass) may differ.

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Old January 25, 2012, 07:25 PM   #14
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I can not speak for .308 as I do not load for it. I do load for .223 and used the OCW method with matching head stamps, and then just as a curiosity did it again with mixed head stamps to see how much of a differance it would make. The results were that the loads were more acurate than I can shoot.

Though the variance between .308 and .223 is probably a big one.

I rember reading part of the reason for his method was you would find a load that could go .3 grains either way with consitantly similar performance if you changed to a different head stamp, or lot of brass.
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Old January 25, 2012, 10:50 PM   #15
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Winchester brass in .308 is significantly bigger than military 7.62 NATO brass. The weight difference I've measured is as much as 33 grains as little as 19 grains. Winchester weight control isn't very tight, spanning about 6 grains in that chambering. In .30-06 the weight difference is much less. I've seen as little as 4 grains difference from LC to as much as 12 grains difference, depending what lot it was. In .223, the difference from other brands is quite small, being within a couple of grains in many instances, which is about like the difference you see in 0.10—0.15 grains of powder. Negligible.
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