SMALL BASE + STD FRONT CAP + 100mm REFLEX + LARGE INTERNAL REFLEX BRAKE. BBG - NF#2 - O16SUGESTED CALIBERSelectADDED LENGTH (mm):157OVERALL LENGTH (mm):258DIAMETER (mm):50WEIGHT (g):608COMPONENTS SelectSUGESTED CALIBER.204 > .220 (-1) .243 > .270 (-2) 7x57 > 30-378 (-3) 7.62 x 39 > .338 (-4) ADDED LENGTH:157mm OVERALL LENGTH:258mm DIAMETER:50mm WEIGHT:608g THREADM12 X 1 M13 X 1 M14 X 1 M16 X 1 M18 X 1 & IMPERIAL