AR FSB (.625) vs (.750)

[HamYankee]

Regarding the two diameter types, is there any disadvantage to one or the other?

 

[lazarus0213]

hate to state the obvious, but they only work with the same sized barrel. So using one on the other doesnt work!

 

[chezuki]

Regarding the two diameter types, is there any disadvantage to one or the other?

Yes. One of them will likely either not fit on, or will easily fall off of your barrel. You must get the correct size for your barrel.



Edit: Scooped by Laz.

 

[HamYankee]

Yeah, I know a .625 won't go on a .750 barrel and visa versa. Anything else? What is more common? Mil spec? Pros or cons to one barrel size over the other?
I guess my question is more about the barrel diameter, not so much FSB because I know one goes with the other.
Are both barrel diameters equally as common?

 

[Jeremy1066]

Yeah, I know a .625 won't go on a .750 barrel and visa versa. Anything else? What is more common? Mil spec? Pros or cons to one barrel size over the other?
I guess my question is more about the barrel diameter, not so much FSB because I know one goes with the other.
Are both barrel diameters equally as common?

The .750" is much more common. It's what the govt./M4 profile uses. Only a true lightweight barrel uses a .625" gas block (like my Spikes).

 

[wsenefeld]

No advantage from the gas block diameter itself. If you want a medium contour or larger barrel, you'll get .750" at the gas block. If you want a true light weight, it'll be .625" at the gas block.

Pick your barrel based on the quality of its materials. 4150, CHF, melonite, HPT, MPI, etc. Don't worry about the gas block diameter. If purchasing from a reputable company, they'll know the proper gas port size.

Gas blocks will also run the same price so no worries there. All but one of my gas blocks are .750" but it hasn't changed my build our build quality in any way.