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Posted: 1/5/2010 6:16:46 AM EDT
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Hi experts! I've been working up a load with MT 55 bullets and about 25 grains of A2230 which is shooting very well with my once fired LC brass. I have quite a bit of PMC .223 brass that I was wondering if I can use as well. Will it work with the same charge or will the pressure be too high? Is the brass the same?
Thanks! |
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I think the PMC will give you a higher pressure due to decreased internal case volume.
I use PMC all the time... but my standard load is so mild, I could go a full over 2 full grains of powder higher and still be good. I like to leave my practice ammo with a lot of top side margin for error for this very reason. |
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LC brass likely has a bit less case capacity than the PMC due to Lc having thicker case wall in the web area (toward the bottom 1/3 or so of the case).
PMC is South Korean made & good quality. So, all things being equal, I suggest a bit LESS powder in the LC cases than in the PMC. Keep an eye on pressure signs. Variations from one production run to the other on brass causes slight differences in metal hardness, case mouth tension on the projectile & so on. All brass is not "the same". Case capacity is your biggest cosideration as to powder charge weight. Cases should be trimed to minimum about each 3rd fireing based on my experience. How "hot" you load & how much pressure your loads produce will influence how much your cases lengthen with each fireing. There are several variables particular to your rifle, cases & load componants that determine what happens to the case upon fireing. Even the air/rifle/cartridge temperature will influence chamber pressure a bit. |
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I wouldn't worry about it unless your shooting for competition since the volume difference is minimal.
.223 Rem Case Weight vs. Capacity Case Manufacturer Case Weight* H20 Capacity** Lake City 06 92.0 30.6 WCC99 95.5 30.5 Sellier & Belloit 92.3 30.5 Remington 92.3 30.4 PMC 93.5 30.4 Hirtenberger 93.7 30.4 Lake City 04 93.0 30.4 Federal 96.3 30.2 Hornady 93.9 30.1 IMG (Guatemalan) 95.4 30.1 Lapua (new lot) 93.4 30.1 Winchester 93.9 30.1 Olympic 97.4 30.0 Radway Arsenal 96.1 30.0 PMP 104.5 29.9 FNM 93-1 97.3 29.8 Lapua (old lot) 104.0 28.0 *info found on 6mmbr.com. |
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Quoted:
LC brass likely has a bit less case capacity than the PMC due to Lc having thicker case wall in the web area (toward the bottom 1/3 or so of the case). PMC is South Korean made & good quality. So, all things being equal, I suggest a bit LESS powder in the LC cases than in the PMC. WRONG! Note the list above. LC has some of the highest case capacity. And almost ALL brands of brass fall so close together it's completely negligible for bulk ammo production. |
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Quoted:
Markm. Thank you for the clairification on LC brass capacity. I have been accepting what others have posted on that. So repeated it. The problem is that the average noob thinks 5.56 brass is has heavy walls analogous to 7.62 brass; it ain't so. You can see from the list on 6mmBR that LC brass for 5.56 ammo is nearly identical to Winchester, WCC, Lapua, and Remington. The situation is the opposite of that for 7.62 brass as it does indeed have less internal capacity than .308 Win, so maximum loads will likely be less than can be used in .308 Win brass. The problem with lists is that things change over time. That means they should be used as a guideline and a smart reloader will check out what he is loading without assuming that it is the same as the samples from someones list. |
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