Be sure they are not using the inner firing range (danger zone 1)! It is marked by a series of smaller cans commonly called the picket fence, they are in a semi-circle until they reach the southern boundry. H Can is located on the south end of the Outer firing range, just out side the south edge of the picket fence. About 1/2 way from the shore to the SE corner of the outer firing range. Here is a link to a map of the firing range so you can see where it is located as well as the picket fence boundry of the inner firing range.

http://wbsa.us/denied/range_map.jpg