Parker 12 ga muzzleloader
Most likely a Belgian gun. Take off the barrels and look at the barrel flats (breech end on the underside of the barrels). If you see the letters 'ELG' inside an oval then it's Belgian.
Standard 16 gauge shotgun shells.
It will be marked on the receiver. It was made in 1980
That should be a tactical or defense shotgun.
Shotgun shells
What kind of shot gun?
This is a Sweet Sixteen Auto-5 made in 1956
You can use nothing but 410 shells in a 410 shotgun.
This is a Browning Auto-5 Shotgun, 16 guage made in 1950. It is chambered for 2 3/4" 16 ga shells
1982. Browning.com has a section under customer service where you can get owner's manuals.
The serial number seems to be incomplet as to which model it is. MP stands for 2008
A Damascus twist steel double barrel shotgun is an antique shotgun made by layering iron and steel and welding them together. This kind of shotgun is worth approximately $3,000 depending on the condition of the weapon.