7.62 NATO vs. .308 Win and 5.56 vs .223

[Barney88PDC]

What are the differences between them respectively and can you shoot them interchangeably? I was told that you can shoot .223 in a 5.56 but not the other way around. Is there a similar rule for 7.62/.308? Any help would be appreciated.

 

[CajunTim]

I have shot 7.62x51 in my .308 Savage 12FV with no ill affects

 

[Barney88PDC]

Well I have a M&P15A and according to the specs on there site (Caliber: 5.56 mm NATO / .223) so I guess I can shoot either. I thought this was the case of any .223 or 5.56NATO. But I had someone tell me not to shoot 5.56NATO in a gun that was marked .223Rem but if it was marked 5.56NATO you were ok to shoot .223Rem or 5.56 NATO in it. Also I went check the Armalite sight for the AR-10A4 and it states in the specs (Caliber: 7.62mm NATO). So would I be doing any harm if I ran .308Win rounds through it?

 

[nola_]

difference is pressure.

 

[CajunTim]

Also I went check the Armalite sight for the AR-10A4 and it states in the specs (Caliber: 7.62mm NATO). So would I be doing any harm if I ran .308Win rounds through it?

For the most part that is all I plan on shooting out of mine. I will let you know next weekend how it works out.

 

[LouisianaCarry]

 

[LouisianaCarry]

With the 5.56/.223, it is not just the noticably higher pressures (like 2800 fps vs. 3200 fps from a 16" barrel), but the pressures combined with a tighter throat. At the very least, you will wear out your throat and have a decline in accuracy. At most, you could hurt yourself. Explosions that could hurt you are uncommon, but SAAMI does list it as an unsafe combination.

If you want the most accuracy, go with a .223 and a .223 chamber, as the tighter tolerances lead to tighter groups- you can shoot .223 in a 5.56 chamber, but you cannot take adantage of the accuracy the .223 was designed for.

If you want self defense increased reliability, go with 5.56, as looser tolerances generally lead to fewer hiccups; not to mention the higher pressures give more reliable fragmentation and increased penetration. Shoot 5.56 if you can find it, but being able to shoot .223 is a plus for logistical reasons.

 

[Barney88PDC]

Anyone have any info on 7.62 NATO vs .308 Win?