You did not specify the make of your Model 300 (there are several), but in general, a 12 g shotgun CAN fire slugs from any standard barrel. You will get better accuracy from a slug barrel, but you could use any barrel OTHER than an "Extra Full", or a shotgun with a variable choke.
the make of the shotgun is Daiwa model 500 it's a 12 gauge
The Model 1878 was offered in 10 and 12 gauge from 1878 through 1889.
If you are speaking of the single or double barrel guns, you can change barrels. However, you should have a gunsmith look at the other barrel to make sure it fits properly, most of them need a little hand fitting.
Most likely Stevens they did make a model #5100
"Gauge" is measured by the inside diameter of the "business end" of the barrel. Make sure it's unloaded first!
depends on make, model and condition
You need to identify the make and model of the shotgun. Dozens of different makes of guns show a browning patent on the barrel. Recheck and re-ask the question - Thank you
1837
Depends entirely on the make, condition and usability.
Yes in 1860 Stevens made a double barrel, all steel barrel and its has external hammers.
We'd have to start by figuring out what make and model it is. What markings are on the gun? sales@countrygunsmith.net
Your Browning auto-5 standard weight shotgun which was made in the year 1946,will bring between 600-675 dollars for a plain barrel model,900-1,000 dollars for a solid matte rib barrel model,and 800-900 dollars for a vent rib barrel model in the condition that you describe.You will loose some value due to the poly choke that was installed on the shotgun,but make it back buy the fact that you have a 16 gauge,instead of the standard 12 gauge.