Armory Sponsor
Posted: 8/11/2012 1:47:56 PM EDT
|
I just got a Sig 716, and I've gone through my stash of brass and found that I have a mix of GI, pseudo-GI (Prvi, PMC, etc) and commercial cases on hand. I want to load a basic M80 equivalent to start with, but I have questions.
First, as has been discussed in the past, there is a difference in at least some GI 7.62 NATO cases and commercial .308 cases. Should I segregate cases based on this alone, or should I figure out which cases are actually heavier (and thus probably thicker) and sort by that? Should I develop different loads for GI cases and for commercial cases? Am I over thinking the issue, or am I just not well enough educated in the differences between 7.62 NATO and .308 Win? Thanks!! |
| if you are going fo tack driving, definitely sort your brass. between commercial and NATO, and between different manufactures the internal dimensions may be different. also, i would check to see if any of them are berdan primed, i did find some in my box of 7.62x51. |
|
So basic blasting loads should be OK with mixed cases, but for accuracy I should sort carefully? That makes sense. I was afraid that there was a very large case capacity difference that would make it mandatory to sort for all loads. I will probably still separate GI and commercial for all my loading, but I'm less worried about the extremes to watch for.
Any experience with stuff like Prvi and PMC brass? Is it closer to GI or commercial? By the way, I'm up to about 75 Berdan primed GI cases, but I also have both the RCBS Berdan Decapping tool and a line on the right Berdan primers for this stuff, so I don't plan on problems in that area. |
|
Quoted:
So basic blasting loads should be OK with mixed cases, but for accuracy I should sort carefully? That makes sense. I was afraid that there was a very large case capacity difference that would make it mandatory to sort for all loads. I will probably still separate GI and commercial for all my loading, but I'm less worried about the extremes to watch for. Any experience with stuff like Prvi and PMC brass? Is it closer to GI or commercial? By the way, I'm up to about 75 Berdan primed GI cases, but I also have both the RCBS Berdan Decapping tool and a line on the right Berdan primers for this stuff, so I don't plan on problems in that area. for plinking 5.56, i dont sort between NATO and commercial, so i dont see why you would need to for 308. as long as you dont go to max load, stick around the starting load for plinking. you may want to scrap or sell the berdan cases, iirc it is almost impossible to get berdan primers. |
|
Resize and trim every case then weigh them to gain some idea as to their compatability. I never mix commercial and military .308. It's a known fact that Lake City brass usually weighs 180 grains unprimed. Winchester commercial can be as light as 155 grains unprimed. A full 2.0 grain reduction in powder charges is needed when switching from Winchester to Lake City using the same bullet.
Other brands of commercial brass usually weigh more than Winchester, but none of them come close to Lake City (and other brands of military brass) in weight. Proceed with caution. |
|
Quoted:
Quoted:
So basic blasting loads should be OK with mixed cases, but for accuracy I should sort carefully? That makes sense. I was afraid that there was a very large case capacity difference that would make it mandatory to sort for all loads. I will probably still separate GI and commercial for all my loading, but I'm less worried about the extremes to watch for. Any experience with stuff like Prvi and PMC brass? Is it closer to GI or commercial? By the way, I'm up to about 75 Berdan primed GI cases, but I also have both the RCBS Berdan Decapping tool and a line on the right Berdan primers for this stuff, so I don't plan on problems in that area. for plinking 5.56, i dont sort between NATO and commercial, so i dont see why you would need to for 308. as long as you dont go to max load, stick around the starting load for plinking. you may want to scrap or sell the berdan cases, iirc it is almost impossible to get berdan primers. DAG Ammo has 'em. The .308s require "large rifle" type primers, in this case the KV762N. Despite most people's opinion of Tula ammo, their primers, particularly the Berdan primers, are well thought of. I already have 1k of the KV24N for loading 7.62X39 (same diameter, different height). |
|
I have gone to all Lake City bras for my POF. It's the best brass out there short of Lapua. there has been too much inconsistency in the commercial stuff. I have been buying it in bulk from Everglades for $160 per 1k. The lots have been all the same year headstamp! I full resize with small based die, swage the primer crimp, trim, chamfer and load. Shoots excellent!
I do have a question for others though. Most of the fired brass is just a couple of thou long. Trimming is always a PITA. I know in bolt guns you want consistency in length for the jump or jam into the lands. But on an AR where there will always be a big jump due to loading to mag length is a couple of thousandths make a real difference? Pressure? Inquiring minds want to know! |
|
After working with one powder, one bullet config, one primer, and one case (1X LC'02) for the past two years, IMO, I will hotrod rounds for Stoner DI autloaders, but not for rigs that use operating rods that perform in compression and with large eccentric in the load path (M1, M1A, M14, SOCOM 16, Scout, etc.). I will take the DIs up to start of early unlock problems. I want to baby the latter because of that operating rod. So, I am going to work on two streams of .308 ammo. as far as powder loads and peak chamber pressures, one for DI and one for M1A.
I have collected enough .mil brass, that I am not going to be intermingling comm'l brass nor worry about 2 gr powder compensation. For my purposes, I will segregate .mil cases into vendor and headface date stamps, and plan on only running up to 3X before scrapping. I've actually come to appreciate the ring crimp on .mil cases, because it provides enough interference even though swaged, so that expanding primer pockets will still have the crimp ring artifact to back up the fit between cup and pocket. IMO it will delay the loose primer syndrome. |
|
Quoted:
Dag is the only place I know of to get the correct size Berdan primer for 308. Price isn't great and the proof of age before ordering was a hassle to get right. Owner was helpful however. I have no help with your loads, sold my M1A when I got onto AR's. There's a vendor at my local gun shows that has both KV24N and KV762N for less than $30/k, so I can get some when I need them, but I'll need larger quantities when I get this figured out. Fortunately, Grafs also has both types of Tula Berdan primers, for about $115 for the KV24N and $150 for the KV762N, while DAG has both for $157 (all of these prices are for 5k case quantities). It's good to see that Grafs has them back and there is at least one more source, despite the hassles... |
|
Glad to hear Graf's has both sizes. Dag's had 7.62x39 Berdan primers available first, then about a month later Graf's had them. I could have saved some money buying from Graf's, but my crystal ball was broken.  But I stacked then deep, won't be needing any more for quite a while. Your local guy sounds like a bargain.
|
Armory Sponsor