That's an 11" with a 5" FH, not a 16" M4 profile barrel with an additional FH. A bayo will flop around loose behind the FH.

I did run across somebody selling an abortion of a bayonet that had an extra portion of handle that extended the length sufficiently that the bayonet ring would rest on the FH. I'd post a link, but I'm having trouble finding it again.

ETA: Here's a discussion from ARFCOM with pictures to show what a true 16" bbl carbine looks like with a bayo. There are also some links to extended bayos that will fit a 16" bbl carbine.
http://www.ar15.com/forums/topic.html?b=3&f=12&t=267686