These single-shot guns dont bring much money, but the magnum with 36" barrel will bring somewhat more than a typical 94F. Figure $75-$125. www.countrygunsmith.net I Bought one today and paid $125. Not worth much money but is a good looking old gun. Couldnt pass it up.
If it's chamberd for 3" magnum shells and the owner's manual says so.
When were 3inch magnum
i just bought one for$85 in fair condition
100-400 USD
100-500 USD
100-10000 USD depending on specifics
Not without specialized tools and equipment that a gunsmith has. Trying to do it with ordinary tools will destroy the frame or barrel.
Assuming that your Belguim made Browning auto-5,20 gauge magnum shotgun is in 98% condition.Iwould assess a value of 925 dollars for this model with a vent rib barrel that was made in 1970.If the gun rates a 95% condition then 850 dollars.
Lets first say that the Browning auto-5 magnum model with the 3inch chamber,in 12 gauge was not available until 1958.If yours has a plain barrel and shows between 60%-90% of its original finish,then the value will be between 365-525 dollars.If it has the vent rib barrel,then the value will be between 450-750 dollars for the same amount of finish.
Whether it is a Savage/Stevens of any other modern shotgun, look on the top or side of the receiver and it will give you that information. For example: on a 12 gauge it will say 2and3/4 inch only or 2 and 3/4 inch and 3inch magnum. The gauge is equal to the number of corresponding lead (as in metal) balls that it takes to equal on pound (troy)
If the barrel is marked for 3 inch magnums, yes. Marked 2 3/4, no.
The value will range between 150-350 dollars depending on overall condition of your Smith and Wesson revolver.