Will a 12" RIS II fit on a 20" bbl w/ FSB?

[samuse]

Quick question.

Will a Daniel Defense M4A1 RIS II work on a 20" A2 rifle barrel with a FSB?

[TehLlama]

The RIS-II is 12.5". I've made that mistake before...

[IZinterrogator]

I contacted Daniel Defense with that same question about a year ago and they said it was good to go to use with a rifle length gas system with FSB.

[samuse]

Cool. Thanks for the info...