bought a ballistic advantage barrel #babl308003m. it's a .308 16" tactical government, mid length barrel, modern series. gas port measures .070 takes a .750 gas block. measured the gas tube length as 11.125, this matches no length on any charts i could find. did go back to ballistic advantage and they list a gas tube for this barrel, but couldn't find the length listed. wondering if the port should be drilled to .085 or .090. maybe with the shorter tube .070 will work?