Charging Gun

FIG. 1 is a front perspective view of a charging gun, showing my new design; FIG. 2 is a rear perspective view thereof; FIG. 3 is a front plan view thereof; FIG. 4 is a rear plan view thereof; FIG. 5 is a left side view thereof; FIG. 6 is a right side view thereof; FIG. 7 is a top plan view thereof; and, FIG. 8 is a bottom plan view thereof. The broken lines in the drawings illustrate the portions of the charging gun, which form no part of the claimed design.