Check with a gunsmith first.
sure - clean it afterward
The Light will only accept and shoot 2 3/4" shells. The Magnum will shoot up to 3" 20ga shells.
The sizes of shells it accepts will be stamped on the barrel
yes it will. the rating shotguns are chambered for is the maximum size shell you can shoot. i have a 1100 LT chambered for 3 inch and i shoot 2 3/4 inch shells out of it mostly.
It will be marked on the barrel.
In general, no. Unless the gun is marked for 3 inch (or even 3 1/2 inch) shells, you should not attempt to fire 3 inch Magnum shells, even if they seem to fit. However, if you have a gun made for 2 3/4 inch shells, and have 2 3/4 inch "magnum" shells, IF your gun is safe to shoot, it should be safe to shoot those "baby" magnums.
Yes. A 3-1/2" chamber will accept 2-3/4" & 3" & 3-1/2 shells
Yes, shorter shells are no problem.
Absolutely not! 2 3/4" only!
You can fire 2 and 3/4 inch shells in a shotgun chambered for 3 inch shells. There is no 3 and 3/4 inch shell made.
YES IF ITS MARKED 3 INCH, THEY NEVER MADE BLACK POWDER SHELLS IN 3 INCH FOR 12 GA GUNS.
Some do, some don't. If the barrel is not marked 3"shells, then no.