12.5 Barrel Length

I have an opportunity to pick up a 12.5" T91. I was going to put my OCM6 on another run of the mill AR, but this way intrigues me more. Only issue is I don't know if there's enough barrel poking out from the handguard to mount the adapter. I think there is, but if anyone has one available and can get a measurement for me, that'd be worth at least 1 internet point.

Thanks!