Front Sight Gas block

[AK Gun Man 88]

Possibly another dumb question. Wife wants a 300 black (carbine gas system) with midlength FSB. Forward of the gas port, the barrel measures .730 inches.

Will a .750 FSB work on .730 in barrel (such as this http://www.armalite.com/ItemForm.aspx?item=EU0240MPKIT)?

Thanks.

 

[madcratebuilder]

A pinned style would not work. A clamp on with some .010 shim stock would work.

 

[TonyAngel]

A friend of mine just built a 16" with carbine gas. He used a Yankee Hill clamp on flip up front sight to install rifle length MOE handguards. It all fit fine.

 

[rcmodel]

Your link opens a black page.

However, it would be very unusual for any AR-15 barrel to be made .730" where the gas block seats over the gas port.

If it is .730" foreward of the gas port?

That means it is .750" where the gas block seats and .730" foreward of that, so you can slip it on over the barrel.

If it is truly .730" at the gas port, you would have to have a custom made gas block to fit it.

rc

 

[JustinJ]

Why not just get a mid lenght gas system to begin with? Does the carbine lenght offer some sort of advantage with the .300?

Another option would be to install a low profile gas block, mid length free float rail and mount a FS on it.

 

[Caliper_Mi]

Lots of people building "dissipator" style rifles do this, check ar15.com. The .02" can be shimmed or taken up with many clamp on sights. I'm putting a front sight at rifle radius on a 16" midlength barrel soon for just such a build. Hoping I have the same success as others appear to have

 

[AK Gun Man 88]

Sorry about that RC...i copied and pasted last night and didn't check to see if it worked. it was a clamp on gas block...and sorry for the confusion of .730 forward of the gas port...i meant to right .730 forward of the gas block position (which is .750)...long shift yesterday at work and my brain and fingers refused to work well together.

JustinJ...did some research for 300 Blackout, Midlength gas is NOT recommended...and she doesn't want a rail system...forgot to put that in the original post last night too.

Thanks to everyone. I was not sure if the clamp would work or not but looks like it will. Some very knowledgeable folks here. Thanks again.

 

[JustinJ]

JustinJ...did some research for 300 Blackout, Midlength gas is NOT recommended...and she doesn't want a rail system...forgot to put that in the original post last night too.

I didn't realize that about the 300 blackout. Its on the want list but not at the top so haven't researched it much yet.

Unless she is set on traditional handguards there are also free floats without rails.

 

[fatcat4620]

Have ADCO turn the while whole barrel down to .675 behind and forward of the gas block (leaving a notch for the retainer cap). Then you can use a .675 pinned front sight.

 

[JustinJ]

Have ADCO turn the while whole barrel down to .675 behind and forward of the gas block (leaving a notch for the retainer cap). Then you can use a .675 pinned front sight.

I believe you mean .625.

 

[fatcat4620]

I do. My bad.