.308 military vs. 308 commercial

Unlike .223 military vs commercial brass which IME the difference for military cases essentially have primer pocket crimped (although I have seen commercial cases with crimps) with no significant difference in internal case volume (case wall thickness) and I used the same powder charges for my AR plinking loads but .308 military case is a different story. If I was loading near max .223 loads, I would probably use same headstamp cases.

The once-fired LC .308 and other headstamp "military" cases varied in weight and internal case volume compared to once-fired commercial .308 cases. When I conducted load development with smaller internal volume cases, I used lower powder charge ranges.

+1 what bds said. I personally use military brass in those type guns and load to milspec. For working up for exceptional accuracy matched civilian brass.

My 7.62x51 brass is always thicker and harder then my 308 brass of any brand. I personally don't use 308 loads in 7.62x51 brass, I use my metric stuff for my 150gr loads and my Remington 308 for my heavier stuff.
Develop them separately and you will never see the increase in pressure.

03fatboy, is it U.S. manufacture surplus? Most of us assume so I thought would ask. If import you may have other issues.

I just start them at the normal starting charge (in a bolt action) I just don't expect them to work up as high as my Rem brass.

And you will have to remove the military primer crimps before you can reload them.

rc

Possibly Not

RA could be for Raritan Arsenal

http://cartridgecollectors.org/?page=headstampcodes#R

Looks like Remington Arms to me. I report you decide.

they're different animals

The SAMMI/CIP maximum pressure for the .308 Win cartridge is 62,000 psi, while the 7.62x51 max is 50,000 psi. Also, the headspace is slightly different. The .308 Win "Go Gauge" is 1.630" vs. 1.635" for the 7.62x51. The .308's "No-Go" dimension is 1.634" vs. 1.6405" for a 7.62x51 "No Go" gauge. The military stuff also has thicker webs which could reduce case volume somewhat. Like the differences between the military and commercial 223.

You can try full length sizing a sample lot of each type of case, trim to equal length and weigh the two separate lots to get an average weight. If one lot is heavier (on average) than the other, it will have less internal space for powder. With the cases FLR and trimmed, the only difference is weight. There could be a slight variation due to the extractor groove but any difference there would be inconsequential. Alternately, you could FLR, trim and weigh cases (fired primer in) and record that weight. Next fill the case(s) with water and reweigh, compare the different batch weights.

If you have access to a chronograph, and some bona fide 7.62 NATO ammunition, clock a few rounds, and using a suitable powder in the 4895 range or 748 range, starting at start load, increase in .4 grain increments until you have matched the velocity. You should be OK.

Of course, keep an eye on your pressure signs as you would, but if you find a suitable load to duplicate the .mil velocities you should be right where you need to be.

Also, and you probably already know this, if you are using military style sporting rifles, it is a good idea to FL resize your cases. Some guys will set headspace for minimal setback, and obtain more reuses of their cases.

The US manufacturers of 7.62 were:

LC Lake City Army Ammunition Plant, Missouri
WCC Winchester
RA Remington Arms
TW Twin Cities (ran by Federal)

then there are dozens of NATO production facilities around the world

Raritan was a depot, not a loading line.

Be careful loading non US production 7.62 and much of it is Berdan Primed. All US production is boxer primed and easily reloaded.

You will probably note a blue tint on case neck and shoulder from stress relieving in the loading process.

IF YOU EVER SEE A CASE WITH BLUE RIM AND BASE AREA IT HAS GONE THROUGH THE STRESS RELIEF LINE UPKSIDE DOWN AND WILL FAIL ON FIRING.

The Canadian NATO is IVI headstamped and is boxer primed. It was loaded on US Gov't contract during Nam and was very accurate ammo.

It's good brass and as soon as you remove the primer pocket crimp you can load it us as you would commercial .308 brass.

Another added benefit to arsenal production .308, at least in the batches of LC I get, is consistency.

After FL sizing, trimming to length, and primer pocket uniforming, the cases have a much more standard weight "band" than a lot of commercial brass.

I sort by .2gr intervals on .308 for my bolt rifle, and it always impresses me how many cases from military producers fall into one ""band". You always have some outside your "preferred" weight ... everything being equal- but with the exception of Winchester, I have yet to find this uniformity in commercial brass.

Good luck on the .308 adventure. Its a fun one !

One word of advice if you happen to load for bolt guns, and auto loaders- never let anyone but you sort the brass, and pack the ammo That way you only have one person to blame when your auto won't feed your precisely fireformed and necksized boltgun brass.

FIRST OFF; There is NO such thing as 308 military !!! Get your terminology correct !!