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Posted: 2/1/2014 9:04:39 PM EDT
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I bought several 1,000 308 L.C. and have started testing loads. Know i understand its thicker brass and the norm is to backoff 1grain but for my bolt gun im there and i see no pressure signs and accuracy is close so i can tell i need to bump it up a bit to hit the node. Is this normal,anyone use your same load weight going from win to lc brass?
BTW I have sorted the cases i am useing and they all weigh 180.0-180.9 grains if that matters. |
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Quoted: I bought several 1,000 308 L.C. and have started testing loads. Know i understand its thicker brass and the norm is to backoff 1grain but for my bolt gun im there and i see no pressure signs and accuracy is close so i can tell i need to bump it up a bit to hit the node. Is this normal,anyone use your same load weight going from win to lc brass? BTW I have sorted the cases i am useing and they all weigh 180.0-180.9 grains if that matters. |
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Win civilian cases can be approx 15 - 20 gr lower in wt on average than military surplus cases, and therefore higher in capacity. Technically you should work up loads for the cases intended. The "school solution" is to drop your charge wts a few grains when switching from civilian to military brass.
My usual loads are not near max so I tend not to make much if any adjustment. How you handle it depends upon the load and the firearm. Always good to be on the safe side, especially if you are new to reloading or using unfamiliar components. Lake City brass is the gold standard for some shooters. For me its Lapua, then Lake City. Some military brass comes from being fired in machine guns with large chambers. You have to lube them well (but not too much) and adjust the full length die down to ensure you resize them (usually meaning bump shoulder back) enough to chamber in your rifle. If you use a case (headspace) gage you can tell ahead of time if it will chamber or not. Or you can set the sizing die at a "custom" setting to ensure the brass fits the specific rifle chamber. |
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Quoted:
Useing imr4895 right now. But am gonna make up some test loads with varget,reloader15, &tac. Just wondering if i should really be backing off that 1 + grain or just hit my marks that worked with wichester brass. Weight your Win case and your LC case. Fill both with water and weight again. Compute the differences and know the difference in volume between the two. |
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I use 40.5 grains of IMR-4895 with 168 grain SMK's. That's the NRA MAXIMUM load using Lake City brass and Winchester standard large rifle primers. Velocity is 2625 fps from a 24" barrel. Much lower from an M1-A (22") and even less from something shorter. Federal 210M primers are virtually identical to Winchester in this combination.
Substituting Remington 9.5, CCI-200 or CCI-250's lowers pressure substantially, however, the NRA advises against raising the powder charge because of it. CCI's military primers are HOT and should be treated as in the same class as Winchester/Federal 210M's. |
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I recently went from PRVI civi .308 cases to LC military cases and laddered a few dozen cases with Varget, starting from -1.5 grs.
I'm at the mid-range of what the Hornady manual calls out for XBR 8028, but I noticed 2" lower point of impacts @200 yards until I was 0.2 gr lower than my standard PRVI case load. Now I load them the same, since I'm in the middle and haven't had any pressure signs. For what it's worth, the powder takes up a LOT more room in the MIL cases, and I'm almost compressing 150 gr Hornady FMJ pills. Also, I suggest the Dylan lube/homemade equivalent if you're sizing 1x fired mil brass. Those machine guns really tear up those cases. YMMV |
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Brass is brass.
Work up your loads and check for pressure signs and velocities with your load I've never treated any brass any different or concerned myself with the thickness discussions. It's been (dis)proven again and again so many times it's not even worth looking at. |
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Quoted:
Useing imr4895 right now. But am gonna make up some test loads with varget,reloader15, &tac. Just wondering if i should really be backing off that 1 + grain or just hit my marks that worked with wichester brass. I think the back off statements are referring to your work up starting points, so if your load was developed in a 56grain capacity case and now you start using 7.62x51 LC brass, which in my case was 54gr capacity, you shouldn't just use the same charge right off the bat. That lower capacity(with same charge) will increase pressure by 4, 5, 6000psi depending. If you are working up and watching pressure signs then I don't think hitting the same charge weight would be a problem. |
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Quoted:
I think the back off statements are referring to your work up starting points, so if your load was developed in a 56grain capacity case and now you start using 7.62x51 LC brass, which in my case was 54gr capacity, you shouldn't just use the same charge right off the bat. That lower capacity(with same charge) will increase pressure by 4, 5, 6000psi depending. If you are working up and watching pressure signs then I don't think hitting the same charge weight would be a problem. Quoted:
Quoted:
Useing imr4895 right now. But am gonna make up some test loads with varget,reloader15, &tac. Just wondering if i should really be backing off that 1 + grain or just hit my marks that worked with wichester brass. I think the back off statements are referring to your work up starting points, so if your load was developed in a 56grain capacity case and now you start using 7.62x51 LC brass, which in my case was 54gr capacity, you shouldn't just use the same charge right off the bat. That lower capacity(with same charge) will increase pressure by 4, 5, 6000psi depending. If you are working up and watching pressure signs then I don't think hitting the same charge weight would be a problem. Yep thats what has happened to. It kinda seems like if people were useing win brass( which i was) the charge is about the same when useing LC. I give the advice of working up loads to but its saves powder and time to know just how far down to start when changeing brass like this. Good info guys. Thanks Another question. I have quite a bit of LR headstamp in with the LC brass. Are you guys seperating them out? |
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