darb Posted January 30, 2014 Report Share Posted January 30, 2014 I am new to reloading. Since the case of the L.C. is thicker I have read to reduce powder by 2 grs. in the Speer manual it says 3%. In the hornady manual it does not say, but there are not as many choices with the 308 Winchester service rifle data v.s. the .308 Winchester data. Lyman states 1-2 grains below max. listed charges. I know when starting out to start at the lower velocities, but what would that be? What are some recommendations? I also will be using the .223 Remington data with L.C. brass. Just for your information 1 Ar-15 has a 20" barrel with 1/7 twist, 2nd Ar-15 has 16" barrel with 1/7 twist and the .308/7.62 has a 24" barrel with 1/10 twist. Thanks ??? Quote Link to comment Share on other sites More sharing options...
98Z5V Posted January 30, 2014 Report Share Posted January 30, 2014 The difference is in the 5.56 NATO vs .223 Rem stuff - not in .308 Win vs 7.62x51 NATO. Quote Link to comment Share on other sites More sharing options...
darb Posted January 30, 2014 Author Report Share Posted January 30, 2014 The difference is in the 5.56 NATO vs .223 Rem stuff - not in .308 Win vs 7.62x51 NATO. Speer reloading manual # 14 308 Winchester "Reduce charges developed in commercial cases at least three percent when loading military brass". Lyman 49th edition: " Shooters should also stay one to two grains below the listed maximum charges due to the smaller volume of GI brass". I am 60 years old and know books are books. I figured it would be a good starting point, but experience is experience. I am trying to get clarification and understanding. Thanks Quote Link to comment Share on other sites More sharing options...
98Z5V Posted January 30, 2014 Report Share Posted January 30, 2014 In light of that data, I think I'll go cut up some 308 Win and 7.62x51 and measure some stuff out, just to see what's going on with the brass. Doesn't make too much sense to lower the powder amount in NATO brass, on this caliber, considering the fact that .308 Win has higher chamber pressures over 7.62x51. Don't know then... <dontknow> Quote Link to comment Share on other sites More sharing options...
shibiwan Posted January 30, 2014 Report Share Posted January 30, 2014 (edited) Doesn't make too much sense to lower the powder amount in NATO brass, on this caliber, considering the fact that .308 Win has higher chamber pressures over 7.62x51. Don't know then... <dontknow> The conventional thought is the mil-spec brass has thicker walls and hence lower volumetric capacity, thus requiring less powder so pressures don't get excessively high (smaller case volume + same charge = higher pressure). I've safely loaded mil-spec (LC especially) with standard loads and they shoot well, with no signs of overpressure. YMMV Honestly, I don't think they are that much different, volume-wise. Edited January 30, 2014 by shibiwan Quote Link to comment Share on other sites More sharing options...
98Z5V Posted January 30, 2014 Report Share Posted January 30, 2014 Found a reference for the difference - and I still ant to cut some up. If a firearms is chambered to the 7.62 NATO spec, it is likely to be unsafe to fire .308 Winchester for the same reasons that it would be unsafe to shoot a rifle that it could swallow a field reject gauge with room to rattle: Excessive headspace allows cartridge brass to flow too far forward under pressure, potentially stretching at the web to the point that the case ruptures, causing an explosion. 7.62x51mm chambers get away with being so loose because 7.62 ammo is made thicker at the base than .308. The extra brass provides enough material to prevent ruptures, and is the reason why most reloading manuals advise downloading by about 10% when using military brass. Conversely, thinner .308 brass provides more case room, but less leeway in chamber dimensions. Good read: http://how-i-did-it.org/762vs308/chamber.html Quote Link to comment Share on other sites More sharing options...
98Z5V Posted January 30, 2014 Report Share Posted January 30, 2014 The conventional thought is the mil-spec brass has thicker walls Thicker base, from what that last thing I found was... Some chopping is about to happen. Quote Link to comment Share on other sites More sharing options...
shibiwan Posted January 30, 2014 Report Share Posted January 30, 2014 Thicker base, from what that last thing I found was... Some chopping is about to happen. Photos pls. :D Quote Link to comment Share on other sites More sharing options...
darb Posted January 30, 2014 Author Report Share Posted January 30, 2014 thanks. looking in the lyman book it show max pressures of 48,800C to 61200C depending on the powder. to me that's a lot of pressure difference but what do I know and that is with Remington brass Quote Link to comment Share on other sites More sharing options...
shibiwan Posted January 30, 2014 Report Share Posted January 30, 2014 thanks. looking in the lyman book it show max pressures of 48,800C to 61200C depending on the powder. to me that's a lot of pressure difference but what do I know and that is with Remington brass What powders? I ended up being about 1gr-1.5gr over the minimum Hogdon data for accuracy loads. Check out http://data.hogdon.com Also the attachment I added may help.load map sierra 308.pdf Quote Link to comment Share on other sites More sharing options...
darb Posted January 30, 2014 Author Report Share Posted January 30, 2014 Found a reference for the difference - and I still ant to cut some up. If a firearms is chambered to the 7.62 NATO spec, it is likely to be unsafe to fire .308 Winchester for the same reasons that it would be unsafe to shoot a rifle that it could swallow a field reject gauge with room to rattle: Excessive headspace allows cartridge brass to flow too far forward under pressure, potentially stretching at the web to the point that the case ruptures, causing an explosion. 7.62x51mm chambers get away with being so loose because 7.62 ammo is made thicker at the base than .308. The extra brass provides enough material to prevent ruptures, and is the reason why most reloading manuals advise downloading by about 10% when using military brass. Conversely, thinner .308 brass provides more case room, but less leeway in chamber dimensions. Good read: http://how-i-did-it.org/762vs308/chamber.html great link good information thanks Quote Link to comment Share on other sites More sharing options...
darb Posted January 30, 2014 Author Report Share Posted January 30, 2014 What powders? I ended up being about 1gr-1.5gr over the minimum Hogdon data for accuracy loads. Check out http://data.hogdon.com Also the attachment I added may help. ok I have four references. I went with IMR 4064 powder and 168 gr. hpbt. 1st lyman 49th edition 40-45gr. 2nd hogdon.com 41.5-45.9gr 3rd Speer manual #14 42-46gr #4 load map sierra 37.8-43.4. I guess it just boils down to trial and error, start low and work up but I still would like a bit more input regarding the 7.62 L.C. brass with the .308 load ^-^ Quote Link to comment Share on other sites More sharing options...
darb Posted January 30, 2014 Author Report Share Posted January 30, 2014 What powders? I ended up being about 1gr-1.5gr over the minimum Hogdon data for accuracy loads. Check out http://data.hogdon.com Also the attachment I added may help. Those were 15 different powders out of the lyman 49th edition with a 12,400C spread in pressure Quote Link to comment Share on other sites More sharing options...
shibiwan Posted January 31, 2014 Report Share Posted January 31, 2014 (edited) ok I have four references. I went with IMR 4064 powder and 168 gr. hpbt. 1st lyman 49th edition 40-45gr. 2nd hogdon.com 41.5-45.9gr 3rd Speer manual #14 42-46gr #4 load map sierra 37.8-43.4. I guess it just boils down to trial and error, start low and work up but I still would like a bit more input regarding the 7.62 L.C. brass with the .308 load ^-^ I'm doing 42.5gr of IMR4064 with 175gr Sierra HPBT. This is the identical recipe for FGMM 175gr and when loaded carefully it gives very consistent results. For 168gr you should be able to up the load by about 1/2 grain. I'm pretty much following the Hogdon data from their site and comparing to the Sierra 308 load map and adjusting from there. Can't be that far off especially if it's the manufacturer of the powder. Load IMR4064-308.pdf Edited January 31, 2014 by shibiwan Quote Link to comment Share on other sites More sharing options...
darb Posted January 31, 2014 Author Report Share Posted January 31, 2014 I'm doing 42.5gr of IMR4064 with 175gr Sierra HPBT. This is the identical recipe for FGMM 175gr and when loaded carefully it gives very consistent results. For 168gr you should be able to up the load by about 1/2 grain. I'm pretty much following the Hogdon data from their site and comparing to the Sierra 308 load map and adjusting from there. Can't be that far off especially if it's the manufacturer of the powder. That is solid information thank you. Perhaps I should stop overthinking Quote Link to comment Share on other sites More sharing options...
392heminut Posted January 31, 2014 Report Share Posted January 31, 2014 Tom, instead of cutting up a bunch of brass why don't you just fill the cases with water and measure the volume that way? Oh wait a minute, that doesn't involve tearing stuff up! Never mind! <laughs> Quote Link to comment Share on other sites More sharing options...
Rsquared Posted January 31, 2014 Report Share Posted January 31, 2014 (edited) ^^^^ <lmao> <lmao> Edited January 31, 2014 by Rsquared Quote Link to comment Share on other sites More sharing options...
98Z5V Posted February 1, 2014 Report Share Posted February 1, 2014 Okay, now here's how it all went down... No $hit, there I was, in a boat in the middle of the lake. I was surrounded by 400 trained EYE-talian Attack Ninjas, and all I was armed with was 2 Soju caps and a box of 20 peppermint toothpicks... :bat: I chopped up some brass tonight. Now, I didn't go about it stoopid - I weighed them out first, just to see if this was going to be worth my time. When the numbers came up different, I got curious. .308 Winchester brass, with primer still in it, weighed 168.0 grains even. 7.62x51 NATO brass, with primer still in it, weighed out at 190.3 grains... I suspect Foul Play. Out came the cut-off wheel. As a general rule, the 7.62x51 NATO is on the left. The .308 Winchester is on the right. In all pics below. I can get macro-stupid with these, if you guys want to see more - the original pics are about 4000 wide, and 5mb in size. Quote Link to comment Share on other sites More sharing options...
Rsquared Posted February 1, 2014 Report Share Posted February 1, 2014 I'll take the pics. Just out of natural curiosity. But I can't help it.................... but to want to know what happened with the Itailians? Please PM me if it's not "politically" correct! I could use a good laugh. Quote Link to comment Share on other sites More sharing options...
Rsquared Posted February 1, 2014 Report Share Posted February 1, 2014 And I mean that in a nice way................................................................. yeah right Quote Link to comment Share on other sites More sharing options...
98Z5V Posted February 1, 2014 Report Share Posted February 1, 2014 (edited) They took a pretty serious ass-whoopin'. I'm just sayin'... First off, I'm in a boat, in the middle of the lake. Trained EYE-talian Attack Ninjas can't swim - it's not in their training manual... I quickly dispatched about 350 of them, just by letting them know that information. Had they not known that, and it not been pointed out, things could have gone WAY differently for me that night. <dontknow> Edited February 1, 2014 by 98Z5V Quote Link to comment Share on other sites More sharing options...
392heminut Posted February 1, 2014 Report Share Posted February 1, 2014 Trained EYE-talian Attack Ninjas? I can see this thread going sideways REAL fast! <lmao> Quote Link to comment Share on other sites More sharing options...
unforgiven Posted February 1, 2014 Report Share Posted February 1, 2014 You cut those cases like a sturgeon... <thumbsup> So what about the "Itralians???? Quote Link to comment Share on other sites More sharing options...
darb Posted February 1, 2014 Author Report Share Posted February 1, 2014 Did you you by chance check the % difference in capacity between the two casings? Quote Link to comment Share on other sites More sharing options...
hdbiker1 Posted February 1, 2014 Report Share Posted February 1, 2014 I became curious with the .223/5.56 cases and found the info for capacities on line, but didn't find anything for the .308/7.62 cases. So I weighed, filled with water and found that for the most part, LC brass whether match, lr or m80 were the same at approx 54.8gr. Win brass had me stumped because I had some that the total weight with primer was 183 (100 or so case) and the rest 162. The capacities were 54.1 and 56.2 respectively. R-P cap. was 55.9. Lapua was 54.5. Fed was 54.6. I also did some other headstamps as well, but don't use them for any comparisons. Mind you, these are my numbers so you might get something different depending on how high you fill with water and such. I don't know of an exact formula for how much powder to use when your capacity changes by a certain percentage, but it has at least given me a guide on where to start and has been pretty close (usually within .5gr). Quote Link to comment Share on other sites More sharing options...
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