If you mean a Remington 512 X Sportsmaster, no. It is for .22 Short, Long, Long rifle cartridges. The .22 magnum is longer, larger in diameter and more powerful.
The Light will only accept and shoot 2 3/4" shells. The Magnum will shoot up to 3" 20ga shells.
If has the magnum cylinder it will.
The sizes of shells it accepts will be stamped on the barrel
In a .44 Magnum revolver, yes. In a semi-automatic .44 Magnum (such as the Desert Eagle), no.
No, they are different sizes.
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.
sure - clean it afterward
Yes, however, they may not cycle thru, and need to be loaded one at a time. Chamber will need cleaning after shooting the shorter magnum cartridge.
A .357 Magnum can shoot .38 Special rounds as well as .357 Magnum rounds.
No, you cannot shoot .44 Magnum and .410 shotgun shells from a Thompson Super 14 interchangeably. The Thompson Super 14 is designed specifically for .44 Magnum cartridges, while .410 shells require a different type of chamber and barrel configuration. Attempting to fire the wrong ammunition can result in dangerous malfunctions or damage to the firearm. Always consult the manufacturer's specifications for compatible ammunition.
Yes, they are all high brass and considered magnum loads
NO