7.62 x 51 NATO

[BGD]

I just received 200 7.62 x 51 NATO cases. Can I load them using 308 Winchester data? I will be shooting them in a Rock River LAR8.

 

[FROGO207]

You could weigh them or weigh the water capacity to make sure they have about the same internal volume. If they do then load them the same. USUALLY they are the same or close to the 308 in capacity and the 308 data will work. If they are heavier or have less water capacity start an extra 10% lower for starting loads. Still always start at the starting load and work up watching for high pressure signs to stay safe. Do not assume a full tilt load will be safe without working up to it.

Use a good light and make sure they are not berdan primed first.

 

[GBExpat]

I just received 200 7.62 x 51 NATO cases. Can I load them using 308 Winchester data?

Yes

 

[USSR]

Depends upon the case used in the load data. If the load data lists a Winchester case, then I would suggest a dropping back a full grain. Any other case used and you should be okay with starting load data.

Don

 

[claiborne]

YES

and yes

 

[jmr40]

With the same powder charge and bullet you will see a little more pressure and bullet speed. If working on a load anywhere near max it would be wise to consider a lighter charge than normal. This is where a chronograph helps.

 

[Jim Watson]

The old (.30-06 era) NRA rule of thumb that for a load found suitable in commercial brass, you should reduce it by one grain of powder for every 11 grains of heavier military case.
Does that apply to .308-7.62? I don't know; but it shows that thicker brass has been known to matter for a long time.

 

[z7]

When recommending to drop back the starting load when using 7.62 NATO brass, I would imagine you should be mindful of what the load data says. Hornady manual gives starting loads much lower than hodgdon for example.

 

[rcmodel]

Regardless of all that, don't reduce the recommended Starting Load an additional grain, and especially not another 10%!

The published Starting Load will be safe in any brass.

rc

 

[dprice3844444]

try to match the head stamps
https://search.yahoo.com/yhs/search...&hsimp=yhs-att_001&type=att_pc_homerun_portal read the supplied threads and make your decision.

 

[USSR]

The published Starting Load will be safe in any brass.

With all due respect, when the load data lists a Winchester .308 case and you are using milsurp 7.62x51 brass, DEFINITELY reduce the charge weight by a full grain. A good example is Hodgdon's load data for .308 with a 168SMK and Varget. A starting load is listed as 42.0gr, which in some milsurp 7.62x51 brass is just too plain close to what a Max load in that brass will end up being.

Don

 

[judgedelta]

The people at LMT told me that .308 and 7.62 are the same and that they changed the markings on the rifles to please their overseas customers. It was always my understanding that 5.56 mil brass was thicker than .223 and that 7.62 and .308 are the same (excluding manufacturing differences, of course). If you have a scale, a couple of different cases, and some water, it is easy enough to check... size 'em before you weigh 'em.

 

[homatok]

I own a Rugger Ranch rifle in 223. I did some research on using military ammunition in it. The bottom line was/is that some commercial rifles were/are chambered for the military round, it is best to contact the manufacturer to check on your rifle! Here are the results of my research, hope someone finds it useful.

5.56/.223 interchangeability
In a nutshell it is safe/fine to fire .223 in a 5.56 chamber but not 5.56 in a .223 chamber. Dimensionally the cases are the same, but because of the bullet used by the military, the loaded rounds for 5.56 may well be longer than the SAMMI dimensions allowed for civilian .223. It all depends on the bullet .

The Difference between 223 Rem and 5.56 Military Cartridges
There is a general misperception by the shooting public that the 223 Rem and 5.56 Military cartridges are identical and are just different designations for commercial and military that can routinely be interchanged. The fact however is that, although somewhat similar, they are not the same.
•The cartridge casings of each have basically the same length and exterior dimensions.
•Mil Spec 5.56 ammunition typically has higher velocity and chamber pressure than the 223 Rem.
•The 5.56 cartridge case may have a thicker sidewall and a thicker head to better withstand the stresses generated by the higher chamber pressures. This, however, reduces the powder capacity of the case, which is of concern to the reloader.
•The 5.56mm and 223 Rem. Chambers, while similar are not identical. The difference is in the “Leade”. Leade is defined as a portion of the barrel directly in front of the chamber where the rifling has been conically removed to allow room for the seated bullet. This portion of the chamber is more commonly known as the throat. Leade in a 223 Rem. chamber is usually 0.085”. In a 5.56mm chamber the leade is typically 0.162”, or almost twice as much as in the 223 Rem. chamber.
•You can safely fire 223 Rem. cartridges in 5.56mm chambers with this longer leade, but you will generally have a slight loss in accuracy and velocity when compared to firing the 223 round in the chamber with the shorter leade it was designed for.
•Problems may occur when firing the higher pressure 5.56mm cartridge in a 223 chamber with its much shorter leade. It is generally known that shortening the leade can dramatically increase chamber pressure. In some cases, this higher pressure could result in primer pocket gas leaks, blown cartridge case heads, and gun functioning issues.
•The 5.56mm military cartridge fired in a 223 Rem. chamber is considered by SAAMI (Small Arms and Ammunition Manufacturers Institute) to be an unsafe ammunition combination and is listed in the “Unsafe Arms and Ammunition Combinations” Section of the SAAMI Technical Correspondent’s Handbook. It clearly states; “In firearms chambered for 223 Rem, do not use 5.56 Military cartridges.” Federal Cartridge is a member of SAAMI and supports this position.
•Federal’s XM193 packaging currently has a warning that states; “For use in standard 5.56 Chambers. Do not use in non-standard 5.56 chambers.” This warning is also listed on the XM193 Product Specification Sheet. Winchester also has a similar warning on their USA brand 5.56 ammunition packaging: “Use only in firearms in good condition designed and chambered by firearm manufacturer specifically for this 5.56 ammunition and so marked on the firearm.”
•It is our understanding that commercially available AR15’s and M16’s, although some are stamped 5.56 Rem on the receiver, are manufactured with .223 chambers. Our advice (if asked) however should be that it is the customer’s responsibility to know what their firearm is chambered for and choose their ammo accordingly.

 

[medalguy]

What was YOUR brass fired in? That will make all the difference in reloading it. All the stuff about whether you can safely shoot .308 in a 7.62 X 51 chamber is useless when you are reloading. All the external (and internal) dimensions of the brass changed once it was fired.

My experience has showed that some mil brass is thicker than some commercial brass, and vice versa. There's just so much variation between manufacturers that any all-encompassing statements aren't worth mentioning. Measure your brass and go from there.

 

[rcmodel]

In my 50 years experiance?

5.56 NATO = Often is the same weight, or lighter then Commercial .223.
7.62 NATO = Universally heavier then commercial .308 brass.
30-06 military. = Almost always a little heavier the commercial 30-06, but not as much as 7.62 NATO brass.

rc

 

[Slamfire]

Military cases can vary a bunch in weight, though commercial cases vary the most. I have Federal NM 308 brass that goes from 155.0 grs a case up to 170 grains. I sort that brass out by weight.

Most military cases are around 175 grains plus a few grains. If your brass, minus the primer of course, weighs that much, you need to be cautious about loads in manuals. These heavier cases will blow primers well before the max is ever reached in a load manual.

I recommend, for your Rock River rifle a load of 168 grain HPBT, 41.5 grains IMR4895/H4895/AA2495, military cases, CCI #34's, OAL lt 2.800". For a new barrel I would start out at 40.5 grains of any of the 4895 type powders and work up to 41.5 grains. You might think 41.5 grs is a lot less than the maximum load given by a load manual, and you would be right. There are two things about this load: 1) it was meant to be shot in a gas gun, pressures that are fine in a bolt gun will likely rip the rim off in a gas gun, and 2) with military brass, 41.5 grains is a maximum load, if not over it.

I suspect this brass was fired in a military chamber, if so, full length size, and full length size in a small base die. There are lots of threads where reloaders acquired once fired military brass, sized the stuff in a standard sizing die, and the brass would not eject after firing.

 

[7mmsavage]

In my 50 years experiance?

5.56 NATO = Often is the same weight, or lighter then Commercial .223.
7.62 NATO = Universally heavier then commercial .308 brass.
30-06 military. = Almost always a little heavier the commercial 30-06, but not as much as 7.62 NATO brass.

rc

I have nowhere near RC's 50 years loading experience, but my experimentation has given me exactly the same results with these three cartridges.

 

[BGD]

I recommend, for your Rock River rifle a load of 168 grain HPBT, 41.5 grains IMR4895/H4895/AA2495, military cases, CCI #34's, OAL lt 2.800". For a new barrel I would start out at 40.5 grains of any of the 4895 type powders and work up to 41.5 grains. You might think 41.5 grs is a lot less than the maximum load given by a load manual, and you would be right. There are two things about this load: 1) it was meant to be shot in a gas gun, pressures that are fine in a bolt gun will likely rip the rim off in a gas gun, and 2) with military brass, 41.5 grains is a maximum load, if not over it.

I will try and find some 4895 powder. All i have now is half pound of Varget and 2 pounds of Benchmark. I am ready for the powder to become more available.

Thanks

 

[Slamfire]

I found Varget a bit slow in my M1a's, residual breech pressure was high enough to cause case head separations when I tested the stuff. However others have had great success. Based on velocity alone, with a 168, a potential load is somewhere between 42.0 and 43.0 grains. Varget is an outstanding bolt gun powder but a bit too slow for my gas guns.

[SIZE="3"][B]M1A Douglas 1:10" Barrel[/B]			
					
							
168 Hornady Match  41.0 grs Varget  wtd Lot 4295 Mixed LC WLR		3-Oct-05
		 			OAL 	2.8	T = 87 ° F
Ave Vel =	2486					 	
Std Dev =	19					
ES =	61					 	
Low =	2447					
High =	2508					 	
N =	12						
rounded primers							
							
168 Hornady Match  42.0 grs Varget  wtd Lot 4295 Mixed LC WLR		3-Oct-05
		 			OAL 	2.8	T = 87 ° F
Ave Vel =	2541					 	
Std Dev =	17						 
ES =	51					 	
Low =	2514					 
High =	2565					 	
N =	12		 				
							
better accuracy							
							
							
							
168 Sierra Match  43.0 grs Varget  wtd Lot 4295 Mixed LC WLR		3-Oct-05
		 			OAL 	2.8	T = 87 ° F
Ave Vel =	2604					 	
Std Dev =	15						
ES =	49					
Low =	2581						 
High =	2630					 
N =	20						
							
case head separations too slow for M1a[/SIZE]

I am of the opinion that faster is better for these 308 gas guns, I have shot IMR 3031, old NRA advice was not to go faster, and it shoots very well in a 308 gas gun. The slowest I would go is IMR 4064. The old staple was IMR 4895 as it was the powder used in the National Match 308 ammunition, both for the M1a and the Garand. Your gas system is compatible with any powder that was appropriate for those rifles.

 

[Mele112212]

FYI I have a DPMS LR308 and use LC brass with CCI #200 primers.
My most accurate load is 168 gr SMK's over 41 Gr Benchmark.
Brass is full sized using Lee 308 Win dies and trimmed to length.

Now for my personal opinion:
Hodgdon's website load data is lawyered down.