Does anyone know of any flip up front sight or railed gas block that will fit the new Bushmaster Superlight 16" barrel? It is a very thin barrel. The diameter tapers from .670 inches at the chamber end to .600, then steps up to .625 at the sight base, and tapers to .570 from the sight base to the muzzle - similar to the original Vietnam era A1 barrel profile. Perhaps there is a bushing or adapter or something I don't know of to make the standard ones fit it.

I recently asked the same question, looking for a low-profile GB that would fit under longer railed handguards.   Heard from two different people that while YHM doesn't advertise their GB's in .625, they can provide them on request.   I talked to J&T about purchasing one of their barrels of the same pofile w/ a YHM low-profile GB already installed - they are supposed to be calling YHM to confirm availability early this week.     However, no reason you can't call YHM yourself, since they sell direct.  I'm just going through J&T since I'm buying the bbl from them anyway.

Rocko

tag

PRI makes a flip-up front sight/gas block for a superlight barrel.  Someone had some for cheap on the EE not long ago.