.700 Barrel FSB Problem Should I Ream Or Shim

[Jason_805]

The Problem I'm having Is my 300 Blackout Barrel I have to run a Low Profile Gas Block under the rail. At the end of the Barrel it measures .700 which I cannot find a gas block with a rail in that size. My choices are to Shim a .750 OR Ream a .625. Unless anyone knows where to find a .700 gas Block. Any Suggestions??

[ar15barrels]

There are no 0.700" ID front sight bases.
If you are talking about mounting a FSB to the barrel forward of the usual gas block seat, the easiest way is to machine down the barrel for a 0.625" FSB.

If you have the means to bore/ream a FSB to 0.700", you could also do that.

[Jason_805]

Thanks for the reply I will have to find a way to ream/bore out a FSB. The Barrel Is Straight Fluted so I don't want to mess with that.