I make my shaders out of sheet metal . I then brown them in side and out . Mine are full lenght , just about 1/2 inch from the muzzle and about 4 inches behind the rear sight . Full lenght is better,you do not get any heat waves off the barrel. On a hot day , 90+ they work good. In my line of work i have alot of scrap and at one time i was making them up and giving them away to all my friends . My not so good friends i would give them the short sets . My under hammer chunker i made the shader out of round tubeing and it fits in slots on the sights . Every one that has not seen it before thinks it is a 4 foot long scope !!