Hey George,
The proper way to fire a "GAT" is to extend the arm at a 45 degree angle, up and away from the head. Twist it (the GAT) 90 degrees inward. Point the muzzle downward. Yell a swear word or two, then begin jerking the trigger as fast as you can in an attempt to simulate an automatic weapon.
By practicing muscle memory, your groups will eventually come together!!
Good Luck!! Ek
( sorry. My little attemp at humor)