I just purchased my first chrono and have only been loading a couple months. I having some difficulty working up consistant loads with the 7 mm stw. But my question is i set it up about 10' from the muzzle. with 72.5 to 73 gr of IMR4831 and 140 TSX or Accubonds getting average of about 3180 fps. I know that should be faster just curious if the chrono is 10 ' away how much does it effect the muzzle velocity reading. This this makes any sense at all..