The best AR15 handguard is going to be completely subjective to the shooter. Are you going for a full rifle length build, mid-length, carbine or a pistol length? Do you want the handguard to utilize M-LOK, Keymod or Picatinny rails? Are you planning on mounting some sort of non-traditional muzzle device? Even if it’s just a blast forwarding device or a suppressor, typically we want to make the device be as flush to the rail as possible so as to not have an awkward gap.
These are some of the questions you’ll have to consider as you set out to get a new AR15 handguard. Even if you’re not building an AR15, these handguards can also be compatible for AR9 and some AR10/AR308 builds.