AR barrel outside diameter

[Storm52]

This is probably a no brainer question, but why do some barrels have a turned down/reduction of the exterior dimension that is located between the gas bock and the muzzle? They may not be on every model but I've seen them on Bushmasters, DPMS and the S&W. Is there something designed to be clamped within that area. It looks like a 'weak point'. Is this merely done to reduce weight by a few ounces?

 

[missingAZ]

The notch is for the attachment of a M203 grenade launcher, largely useless on a civilian AR.

But damn cool if you got one (grenade launcher that is).

 

[Storm52]

Thanks for the info. Could probably manage getting second hand grenade launcher on Ebay, but highly doubt having access to load anything in it!

 

[charlie12]

The notch is for the attachment of a M203 grenade launcher, largely useless on a civilian AR.

But damn cool if you got one (grenade launcher that is).

And they're fun to shoot.

 

[Bam Bam]

Stom52,

I hate that look of the barrels with the notch in them like that too. Yeah it would be cool to have a M203 hanging under there, but not likely gonna happen nowadays! Give me a HBAR profile any day!







Bam Bam