Shop › PWS .578X28 PISTON BLK PWS .578X28 PISTON BLK $69.95 Primary Weapons Systems Piston, Fits .578X28, Anodized Finish, Black PISTON-578X28 Quantity: Add To Cart Added! Primary Weapons Systems Piston, Fits .578X28, Anodized Finish, Black PISTON-578X28