I think he's a great fig, one of the best Deluxes.
The gun is attached to his right hand with a single Phillips- (cross-) head screw. Once you remove the screw, the gun comes right off. He can't hold it in that hand anymore, but the gun grip has a peg on the other side that fits perfectly into his left hand (the gun rests between his rear wheels in alt mode, and it pegs into the hand there anyway).
You can even make the gun into a shoulder cannon; it's a little hard to explain, but if you flip the barrell allthe way around, you should be able to use the tow hook to latch onto the underside of his back (his windshield), and rest the cannon on the gray shoulder pads. Looks cool:
Click to view attachment Click to view attachmentHe's got great poseability, and can do some cool crouching poses. He can really tow other Dlx cars in alt mode, too. You might want to get the movie battle scenes version, which has more accurate markings, including the correct "Mike's Towing" name and phone numbers on the doors.
I don't think there's anyone who does not like Longarm. Go get him, if you lik ethe movie Deluxe figures, you'll love this one. HTH