It doesn't matter. Most self defense takes place inside 7 meters. At that range shotgun loads have not had a chance to spread to any siginificant degree.
Not unless you have to change the choke tube.
They are for the choke wrench most likely. Choke markings are usually on the body of the tube.
Soak in diesel overnight to loosen dirt/debris, use choke key supplied with gun
Try want ads, gun shows, e-gunparts.com, gun shops
Choke tubes are round case-like devices that tighten the pattern of BBs as they leave the barrel of a gun. The tighter the pattern, the better its long-distance accuracy will be.
DO NOT ATTEMPT TO FIRE BUCKSHOT OUT OF A THREADED BARREL WITHOUT A CHOKE TUBE INSTALLED!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Danger, Danger, Danger
Try Mid West Gun Works.
criminals in most cases. Personal defense in others.
From Mossberg's website:"Can I shoot slugs or buckshot through a "smoothbore" field barrel with Accu-Choke™ tubes? (500/505/535/9200/88/930 models) Yes, and with sabots or rifled slugs, the more "open" the choke tube, the better the accuracy ("Improved Cylinder" recommended.) The "full" or "modified" choke tubes are preferred for buckshot loads. Slugs, buckshot and steel shot loads are not recommended for use with an extra full "turkey tube" installed, due to the tube's tight constriction. Do not fire any load without a choke tube installed, doing so will damage the internal choke tube threads. "
Full choke.
Even in a situation where you shoot some one in self defense the police must take control of your gun. Receiving the gun back will depend on the full out come of the situation.
The same as it is with any manual action gun - it allows the firer to adjust the shot pattern as they see fit, and makes the gun more dynamic, allowing the same gun to be as readily usable for waterfowl as for big game.