This shotgun has a significant military history; this model was used in WW1, WW2, Korea and Vietnam. This shotgun has a slam-fire feature (meaning: if you are holding the trigger when you chamber the round it will fire.) The slam-fire feature was what made this a desirable shotgun, sadly due to accidents Winchester removed this feature in later firearm models. This is still a fully functional firearm.
 
Reference Link: https://www.youtube.com/watch?v=Eq6BrMVELMs