Look at any guage you like. If the odometer works, look at that to estimate when you need to fill up.
Check the receiver
Proofhouse.com has sn tables you can look it up on.
You need to have a gunsmith look at it.
12
There are many different models of 12 gauge shotguns for sale at online retailers like Amazon and GunBroker. One can also check online at eBay for 12 gauge shotguns which are for sale or trade.
12 gauge the higher the gauge the thicker the item is
12 gauge is thicker than 14 gauge.
12 gauge is thicker than 20 gauge. The lower the gauge, the thicker the sheet metal or wire.
12 gauge by far
The 12-gauge is thicker.
I like buck shot. OO.