Good morming Ladies & gentlemen: Many have taken issue with my remark that merely racking the action has a strong psychological effect, I agree that not evey time, but most of the time it is quite effective. Only in a stake out is the noise inadviseable. Remember, 99 % of the baddies do not wish to get into a firefight for many reasons, racking the action indicates audibly that you are prepared to do so.
In a practical sense, unless you keep the shot gun loaded with one chambered, and cocked, you will have to rack it - of course, if you are using my personal favorite, My ole Winchester 97 riot gun, you merely thumb back the hammer, also it will fire each time that the action comes to battery if you hold back the trigger - you can get off 2 -3 shots in perhaps a sec if necessary. NOW 'that' is firepower. 24 - 36 9 m/m rounds per sec. hehhe.
Don Jose de La Mancha