5.56 v. 223

[Kenny474]

No dimension difference, only difference in the case is the 5.56 has beefier webbing at the case head to handle higher pressure. The .223 chamber's dimension's are tighter, which is supposed to give better accuracy. The 5.56 chamber is a little bigger and throated differently to handle higher pressure.

If you do a google search you can find all of this information.

 

[bpm990d]

7.62 & .308 have a different dimensions on the headspace gage as does 5.56 mm and .223. Also the chamber drawings specify a different throat.

B

 

[Gonzo]

Sooooo.......we ever gonna get a list together of rifles other than AR variants that can reliably shoot both?

 

[Du510]

7.62 & .308 have a different dimensions on the headspace gage as does 5.56 mm and .223. Also the chamber drawings specify a different throat.

B

My VTR is marked for .308, and when asked, I got the following reply from Remington:

---------------------------------------------------------------
Response (Kiersten) - 03/10/2009 07:58 AM
Matt,

Thank you for contacting Remington. Yes you can properly use 7.62x51 in your VTR. Please let us know if we can assist you with anything further.

Thank you,
Kiersten

Just FYI, I guess.

 

[bpm990d]

for 308 Win., SAAMI says 62,000 PSI chamber pressure, evaluated with a piezoelectric-transducer system.

The mil spec from the early 90s for 7.62mm M-80 Ball says 50,000 PSI chamber pressure evaluated with a copper crusher method and 52,940 PSI chamber pressure using a EPVAT (a type of piezoelectric-transducer) system.

I'm not sure that the systems can really be compared and the chamber and throat dimensions are different, but I'm not surprised they said it's ok to shoot 7.62MM NATO in a bolt gun.

I think much of this is a lot of F.U.D. If you shoot a cartridge and it locks up the action and the primer is flat, it's probably too hot. Don't shoot any more. If you have a .223 rifle and you shot 1500~2000 + rounds through it, it's probably got a throat washed out further than the NATO drawing. 5.56 is probably ok to shoot.

B