The Collaborative International Dictionary of English v.0.48:

Undercharge \Un`der*charge"\, v. t.
   1. To charge below or under; to charge less than is usual or
      suitable for; as, to undercharge goods or services.
      [1913 Webster]

   2. To put too small a charge into; as, to undercharge a gun.
      [1913 Webster]

   Undercharged mine (Mil.), a mine whose crater is not as
      wide at top as it is deep. --W. P. Craighill.
      [1913 Webster]