TM   5-2815-241-34&P FUEL  INJECTOR  -  CONTINUED ACTION LOCATION ITEM REMARKS 14. Barrel  (1) CAUTION Do  not  use  crocus  cloth  or  wire  brush  on  barrel  contact  area  surfaces. Using  lapping  plate  and  cutting  fluid,  lap slightly  to  check  barrel  surfaces  for  mutila- tion and flatness in area shown by black area in  illustration  below. After lapping slightly, If mutilation or unevenness  exists,  replace  plunger and  barrel. CUP  CONTACT  AREA  OF  BARREL A-DIAMETER B-DIAMETER C-DIAMETER D-DIAMETER IN.  (MM) IN.  (MM) IN.  (MM) IN.  (MM) 0.400 0.540 0.710 0.820 (10.16) (13.72) (18.03) (20.83) T A    2 4 2 5 7 8 2-359