Plain Plug Gauge for Cannulation ID of the Gun Drilled Nail (Go Size 4.309 to 4.315 Cyl. 0.003 Len. 50 to 51MM NOGO 4.585 to 4.600  Cy. 0.007 Len. 10 to 11 or Std.  Gauging are should have lapped finigh. Gauge No. PPG 4300.4600 