Lyman 57GPR Receiver Sight SPECIFICATIONS BRAND: LYMAN CA PROP 65: YES GUN SIGHT TYPE: IRON SIGHT GUN SIGHT WEAPON FIT: GREAT PLAINS DESCRIPTION Improve your accuracy with a Lyman receiver sight. The most popular black powder receiver sight offers an immediate improvement in accuracy for the target shooter or hunter. Features 1/4 minute micrometer click adjustments for elevation and windage, quick release slide. 57SML fits perfectly on Lyman Deerstalker or Trade Rifle. Other models may require minor drilling and tapping depending on manufacturer. 57GPR fits Great Plains with supplied adapter.