I have an AR15 SPR with a 15inch Geissele MK14 M-Loc hanguard. It has a 18inch FN CHF chrome plated barrel with a rifle length gas system. I have a 3 inch picatinny rail section that can be mounted flush with the muzzle end of the handguard. Is that the best place to mount it and the bipod? Is it better to move it back a few inches from the end of the handguard? Where is the best place to mount it and the bipod for the most accuracy?