Depends on what is marked on the gun.
Deer slugs are the shotgun shells to use when deer hunting.
That is the rear end of the barrel where the shell is inserted.
It will be marked on the barrel.
Generally, no. While single shot rifles MAY have the rifle barrel replaced with a shotgun barrel, reverse is not true (usually) A rifle cartridge generates much higher pressures than a shotgun shell.
Sorry- that is a serial number, and conveys no information. If the barrel is not marked, you need to take it to a gunsmith who will measure the chamber- not only for gauge, but for the correct shell length. Just because an unfired shell fits does not mean it is the correct shell. And it is not a rifle, but a shotgun.
Should be marked on the barrel
When a shotgun fires, the trigger is pulled, causing the firing pin to strike the primer of the shotgun shell. The primer ignites, creating a spark that ignites the gunpowder in the shell. The gunpowder rapidly burns, producing gases that propel the wad, shot, or slug out of the barrel of the shotgun.
To load a single-barrel 12-gauge shotgun from the early 1900s, first, open the action by breaking the barrel down, then insert a shotgun shell into the chamber. Close the action securely to ensure the shell is properly seated. To unload, open the action again to extract the spent shell, either by hand or using an extractor if equipped. Always ensure the firearm is pointed in a safe direction during this process.
When a shotgun is fired, the trigger is pulled, causing the firing pin to strike the primer on the shotgun shell. This ignites the gunpowder in the shell, creating a rapid expansion of gases that propel the shot or slug out of the barrel. The blast of the gases also causes the action to cycle, ejecting the spent shell casing and chambering a new shell if the shotgun is semi-automatic or pump-action.
England, impossible to give value without name of maker.
a slug is normally use in a shot gun and they are not rifled a gun with a rifled barrel should shoot a Shell that is the same caliber as the gun.
Close the shotgun action and insert a rod down the barrel to the standing breech (to the rear edge of the chamber or where the back of the shotgun shell would be). Mark the end of the rod protruding from the barrel. Remove the rod and measure its length. Per federal law (GCA 1934), this must be a minimum of 18"