I have a question, I have a 14.5 barrel with a permanently attached FH, will I be able to install a LaRue 7.0 FF handrail, and if I can how do you  clean the barrel under the rail, after a long day at the range under the rail? thanks

Not unless you remove the FH.

I don't think there is any way to get a Larue to work. In order for a free floating handguard to be installed you have to remove the front sight base. With a permanantly attached flash suppressor, this is all but impossible.

I had the exact same problem. I run a 14.5 inch Bushmaster upper with pinned Phantom. I chose the Troy industries MRF-C and it works very well. There are some benefits running this system over a Larue including installation without having to remove the front sight base and a removeable bottom rail for cleaning. The troy MRF-C is probably going to be your best option unless you want to get that flash suppressor off somehow.

For what it's worth, I met Mark Larue at the Modern Day Marine expo this past thursday and asked him if was considering making a 2 piece setup for those of us with pinned suppressors. The answer was no. :(

TS

It is possible to have a gunsmith remove your FH and then install the Larue.

I would advice you to go the Troy or RAS II or ARMS route instead.  None of these systems require removal of the front sight, and all are top notch.  The RAS II and ARMS require no modification of the weapon.