Posted by  NightD.Gray-Man
                        
                           
                        
                     
                    Are you aware of the many weapons that dont shoot bullets but still uses ammo? 
                    
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 Yes they have substitutes instead.  
Artillery Cannon: consumes one bullet per shot. (has a grenade in place of bullet)
Egg cannon: (see above.)
Etc.
With the flamethrower it is a little bit more complicated.