.223 is 5.56x45; .308 is 7.62x51.
7.62 Nato, is safe to shoot in .308 chambered rifles, because it has a lower pressure, no problem..
.308 has a higher pressure than 7.62 Nato, however, many people shoot .308 in their 7.62 Nato chambered Garands, and M14/M1A's..
In cartridge terminology, the first number is the diameter of the projectile.
The second number is the case length.
7.62x39 = A .30 caliber projectile in a 39mm case.
5.56x45 = A .22 caliber projectile in a 45mm case.
7.62x51 = A .30 caliber projectile in a 51mm case.
Wasn't trying to teach an engineering or history lesson, just trying to explain why some cartridges are represented the way they are.Davek1977 said:Which is ALMOSt right...aside from the 7.62x39 ACTUALLY using a .311 diameter bullet.....because nothing in life can be THAT simple, especially when it applies to cartridge designations!!nalioth said:In cartridge terminology, the first number is the diameter of the projectile.
The second number is the case length.
7.62x39 = A .30 caliber projectile in a 39mm case.
5.56x45 = A .22 caliber projectile in a 45mm case.
7.62x51 = A .30 caliber projectile in a 51mm case.
And don't forget there are in-between 5.56/.223 chambers. They go by various names depending on the manufacture, Wylde (I think Rock River) and Armalite chambers come to mind. I think Bushmaster may have their own too.AR is chambered (most likely) in 5.56 and therefore it is safe to shoot either one... it is only the rifles that are specifically chambered in .223 (most will be target/varmint bolt guns) that you (supposedly) have to worry about...
And don't forget there are in-between 5.56/.223 chambers. They go by various names depending on the manufacture, Wylde (I think Rock River) and Armalite chambers come to mind. I think Bushmaster may have their own too.
That's my understanding too.True, but from my understanding the only chamber that it is "unsafe" to fire a 5.56 from is specifically a .223. the "in-betweens" and 5.56 can shoot either safely
the 7.62x39 ACTUALLY using a .311 diameter bullet.....because nothing in life can be THAT simple, especially when it applies to cartridge designations!!
Don357....some 8mm Mauser rounds have a 318 diameter bullet.
Many or most Mauser 98 rifles were bored out to .323 by 1905.some 8mm Mauser rounds have a 318 diameter bullet.