Over heard @ gun counter

[Zundfolge]

Here's how I've always heard it.

.308 is higher pressure than 7.62NATO so shoot all the 7.62 out of either .308 or 7.62 guns you want, but don't shoot a lot of .308 out of a 7.62 chambered gun.

.223 vs 5.56mm is the opposite. The 5.56 is the hotter of the two so don't shoot it out of .223 chambered guns.

[UrbanWolf]

Here's how I've heard it.

.308 is higher pressure than 7.62NATO so shoot all the 7.62 out of either .308 or 7.62 guns you want, but don't shoot a lot of .308 out of a 7.62 chambered gun.
.223 vs 5.56mm is the opposite.

I thought people shooting 308 out of M1A, FAL, and SCAR H all the time.

[sniper7]

They are close enough to not make an issue out of it. they are reasonably safe to shoot in each others chambers.

same with 556 and 223. there are some differences and you aren't supposed to shoot 556 in a 223 chamber but i have seen it done and it worked out...

[wctriumph]

Unless the guy behind the counter is a total liar, I keep my mouth shut and go on about my business and stay out of the dealer's business.

[brutal]

If I hear any big safety issue BS I will open my mouth.

[SuperiorDG]

Which one are you?

[SAnd]

.308 is a commercial round made under the voluntary SAAMI specifications. The SAAMI pressure specification is the maxi mun pressure. You can get a wide variety of loads for the .308, including many that are over the 7.62 NATO spec. If you pick the right .308 load it should be OK to use in a 7.62 NATO gun. Generally it is easier just to buy 7.62 NATO spec than figure out if the particular .308 load is the correct pressure for your gun.

The same goes when shooting 30.06 ammo in a military gun. There is a lot of 30.06 ammo that is a lot hotter than is meant to be run in some military guns chambered in 30.06.

[spqrzilla]

The problem is that military specifications for ammunition pressure use a different protocol than does SAAMI. Also, a lot of military specification sheets read "PSI" for pressure when in fact they are spec'ing CUP units. Nominally, 7.62 NATO ammunition pressure limits are lower than .308 Win but the allowable variations under the pressure testing protocols are such that the specs are close to the same. So its hard to compare 7.62x51 NATO specifications with .308 Win. In reality, most .308 Win is within 7.62 NATO specs. So I think that its not an unfair simplification to say that they are the same. That said, I'd be careful of using .308 Win commercial ammo in an M14/M1A rifle as if the pressure curve is late with slower powders, not unlike the problem with Garand's, you can have op rod damage over time.

5.56mm ammo is spec'd for a longer chamber leade than .223 Remington SAAMI ammo so I'd pay more attention to a 5.56mm/.223 question and be cautious about using 5.56mm military ammo in a commercial .223 Remington chambered rifle.

[Rabid]

The problem is that military specifications for ammunition pressure use a different protocol than does SAAMI. Also, a lot of military specification sheets read "PSI" for pressure when in fact they are spec'ing CUP units. Nominally, 7.62 NATO ammunition pressure limits are lower than .308 Win but the allowable variations under the pressure testing protocols are such that the specs are close to the same. So its hard to compare 7.62x51 NATO specifications with .308 Win. In reality, most .308 Win is within 7.62 NATO specs. So I think that its not an unfair simplification to say that they are the same. That said, I'd be careful of using .308 Win commercial ammo in an M14/M1A rifle as if the pressure curve is late with slower powders, not unlike the problem with Garand's, you can have op rod damage over time.

5.56mm ammo is spec'd for a longer chamber leade than .223 Remington SAAMI ammo so I'd pay more attention to a 5.56mm/.223 question and be cautious about using 5.56mm military ammo in a commercial .223 Remington chambered rifle.

^This^

[Hound]

Great read guys. I knew the 5.56/.223 issues but had not gotten around to researching .308/7.62. I learn so much here!