One of the more powerful, and most fun weapons in the Resident Evil series. The gatling gun is capable of firing several rounds per second. The only downside is that it takes about a second for the turret to start spinning before it will fire.
It's good against slow enemies or those at a good distance from your character. Anything fast or close will be able to attack your character as they lift and start up the gun.
If you are good at Resident Evil 2 then you can earn yourself this weapon... of course if you cheat with a gameshark or someone else's saved game then you probably will be able to "earn" it too... :p But most mostly you'll want this weapon to tear at enemies at a distance while reenacting scenes from Terminator 2... :)
To gain it by either character, you need to beat a B scenario with an A rank and no saves. When you finish you will be told you have the weapon.