Quote Originally Posted by gotm4 View Post
Yes a 10" rail/tube will completely cover a midlength gas tube and gas block on a midlength 16" barrel.
It would cover a short gasblock like the Vltor/Noveske. You would need an 11" to completly cover a chopped FSB or the new DD clamp on gasblock.

I'm running rails a little longer to protect the gasblock better. I also dimple the barrel for setscrews. Pinning the GB is not a bad idea either.