They are for the choke wrench most likely. Choke markings are usually on the body of the tube.
The USA has a 25 cent coin which most people refer to as a "Quarter", ie. one quarter of a Dollar.
If you mean quarter of an hour, ie one fourth, it's 15 minutes.
it is 15/60 of a minute ie a quarter.
Can a state pass a gun ban? Yes, but it would considered (by most people) unconstitutional. That's what the Heller lawsuit was about.
The use of steel shot doesn't directly have anything to do with a "Belgium" made shotgun barrel. The only significance is that the gun/barrel was manufactured in in Belgium. The problem with steel shot can be a problem with any shotgun made before the steel shot came into use. The problem has to do with the choke. The use of lead shot shells didn't pose a problem because lead is soft compared to steel. The choke is a constriction at the end of the barrel that can change the shot pattern of the shot shell pellets. The inside diameter of a typical 12 gauge shotgun is about .726 +or- a few thousandths. The constriction of a full choke is about .030 thousandths tighter with a diameter of about .696 Steel shot doesn't compress the same a lead and as a result can damage an older gun not designed for steel shot. Most older guns can handle steel shot if they have a more open choke for example an Improved Cylinder choke. Another alternative is to use another non-lead alternative ie. bismuth. Even with new guns you shouldn't use Full Choke with steel. Modified Choke will generally produce relatively tight patterns with steel. If the gun has some collector value, don't take a chance. If you are determined to hunt with it and want to shoot steel shot, see a gun barrel specialist like Ballistic Specialties in Batesville Arkansas. They can do anything just about with a shotgun barrel.
Half of 4 = 2 Quarter of 4 = 1 Eighth of four = 0.5 (ie a half)
Any real gun can shoot through walls. Depends on size of gun and what the wall is made of.
Quart gets its name because its a quarter of a gallon ie 2 pints.
Ernie Pyle was shot by Japanese machine gun fire on Ie Shima.
That question is too vague. Most states are different and it also depends on what type of gun you want, ie. Shotgun, Pistol, High-Powered Rifle, etc.
Possilbe, but, why?
I have a SKB semi automatic shotgun and was looking around for extra choke tubes for it as it came only with a full choke. I had some Browning Invector (not plus) tubes and the threading was the same and fit right in. I don't have the website anymore but on cross referencing, it stated that the Weatherby and Winchokes had the same threading and would fit. These are all tubes that are designed to fit inside the barrel and not extend out beyond the end of the barrel ie. Invector + or some of the competition tubes. Anyway, my experience is that the Invector works fits just fine, shoots without a problem, although the gun companies will tell you to not interchange. I cannot argue with that so am not encouraging you to use another brand, just giving you my personal experience and what I have read. I have a SKB semi automatic shotgun and was looking around for extra choke tubes for it as it came only with a full choke. I had some Browning Invector (not plus) tubes and the threading was the same and fit right in. I don't have the website anymore but on cross referencing, it stated that the Weatherby and Winchokes had the same threading and would fit. These are all tubes that are designed to fit inside the barrel and not extend out beyond the end of the barrel ie. Invector + or some of the competition tubes. Anyway, my experience is that the Invector works fits just fine, shoots without a problem, although the gun companies will tell you to not interchange. I cannot argue with that so am not encouraging you to use another brand, just giving you my personal experience and what I have read. Briley still make choke tubes for SKB