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Reloading 7.62 v 308

grunt0311

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May 25, 2008
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I have tried some searches and didnt come up with any. I do have some questions about differences in reloading both of these. Is there any difference in using 7.62 NATO v the 308. I would like to use the 7.62 LC brass in my spec builds. Would this cause any problems with chambering, firing, or chamber pressure being too high? Any help with greatly be appreciated. Thank you.
 
Re: Reloading 7.62 v 308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: USMC Grunt</div><div class="ubbcode-body">I have tried some searches and didnt come up with any. I do have some questions about differences in reloading both of these. Is there any difference in using 7.62 NATO v the 308. I would like to use the 7.62 LC brass in my spec builds. Would this cause any problems with chambering, firing, or chamber pressure being too high? Any help with greatly be appreciated. Thank you. </div></div>

For purposes of reloading and component choices, they are the same. Much like 556 vs. 223, you have staked in and sealed primers, sealed bullets and in the case of 7.62 NATO, 'lower' pressures. There are some chamber dimension differences ah la 556 vs. 223, but generally Milsurp 7.62x51 is a lower pressure round relative to SAAMI/Commercial offerings.

Milsurp brass can be heavier/thicker, so you have less internal case capacity and you'll want to drop your charge by 5-7% and work up if you're going to be using load data that uses commercial brass.

Dies, bullets, brass, it's all the same for the reloader.

Chris
 
Re: Reloading 7.62 v 308

Im also trying to duplicate the M118LR. So I shouldnt have any problems with doing that? I know I probly should go little less than what that round is to make sure everything is good before I start to add more powder thats required for the M118LR? And for the 5.56 I shouldnt have a problem either shooting the M855 round out of my AR15 then?
 
Re: Reloading 7.62 v 308

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: USMC Grunt</div><div class="ubbcode-body">Im also trying to duplicate the M118LR. So I shouldnt have any problems with doing that? I know I probly should go little less than what that round is to make sure everything is good before I start to add more powder thats required for the M118LR? And for the 5.56 I shouldnt have a problem either shooting the M855 round out of my AR15 then? </div></div>

Well, LC brass isn't the most uniform brass out there, but figure on the 175 SMK at what...2650 fps through a 24" barrel? Use FGMM 210Ms and any of the three powders...RL-15, IMR 4895 and/or Varget to get you there.

Depending on your AR-15's chamber, M855 should be fine in 556 chambers, but SAAMI has a technical bulletin out that states that it's UNSAFE to shoot 556 ammo out of a commercial 223 chamber and some AR-15s, like my Colt SP1 sporter, have 223 chambers. Most do not, however.

Chris
 
Re: Reloading 7.62 v 308

Thank you for the info. I was planning on using the RL15 to start out with and the 175 SMK. Is the primer, FGMM 210, does this duplicate the primer that is being used in the M118LR? RL15 is the powder that is being used now in that round, plus thats what I see most people are using. How can I tell if there is a chamber that is 5.56. I do have an SP1, but Im shooting the 55 gr bullet our of that. I also have the AR15a2, now that is probly .223. I also have built two other AR's using Colt barrels. Are these .223 or 5.56? Is there anyway to identify markings of some sort that makes it a .223 or 5.56 barrel?
 
Re: Reloading 7.62 v 308

The LC brass will work, but when your LC brass is tired and spent, stick with commercial .308 and .223 brass. I've settled down to using Winchester brass because it's both more affordable and more available in my locale. Rem works fine too. Sticking with commercial brass is just simpler in the long run.

Duplicating loads as not as simple or as rewarding as one might think. It is well worth the time, expense, and effort to develop loads that are based on what your rifle likes, as opposed to some ideal generic rifle that's somewhere out there, but not what you're actually shooting. It's just more effective in the long run.

Each cartridge will like its own bullet, powder, and primers. That being said, W748 will work quite well enough in both, and the 175SMK/.308 and 52SMK/.223 are pretty neato at the distances where the two calibers are most effective. W748 is apparently the best close equivalent to WC750. Simpler is better. I'd even suggest 168's in the .308 unless you're going to be shooting way out into transonic territory. As for the .223, while it will perform out there, and can employ heavier bullets with some success, it's not my choice for LR. I tend to see it as effective to 300yd, and that's the name of that tune.

As a spinoff of the primer shortage, I've been doing my load development lately with Plain Jane standard primers rather than match primers. I then try match primers to see if there's any more accuracy as can be wrung out that way. Often as not, there isn't; and I've got a whole new degree of respect for the 'standard' primer.

When you think about it, a well developed match load is tuned to one of the barrel's accuracy nodes, and should be more tolerant of small component variations. If the development is done right, a reliable brand of standard priemr shoule be consistent enough to meet such a criterion.

Greg
 
Re: Reloading 7.62 v 308

Greg I like your advise. Im sure that it will be cheaper in the long run as well too to stick the the commercial brass and standard primers. I have been reloading for years now and have done well with loads that work in my Rem 700P, M14, and ARs. I do have spec rifles that have been built and will be built in the future. I was trying to see if there is a difference in shooting with different brass/primer/powder. Ill give this a try and see what happends. Probly all in all the standard and the commercial will shot just the same as the military brass/primer/powder.