I'm taking a spare 870 shotgun and building it into a HD gun. I'm ready to install the extended Mag and cut the barrel to 18 1/2 inches. I'm debating on which sight to buy. I want a perminant install and do not want a magnetic device holding it on. I might just go with a brass bead. The barrel is round without a rib. Any ideas on which way I should go with this. Does Truglow make a sight that is a permanent install?