What is the difference.....

[ELITEofWarman8]

What is the major difference between the 12 gauge, 16 gauge and 20?

 

[varelse]

https://en.wikipedia.org/wiki/Gauge_(bore_diameter)

Google is your friend

 

[Missourian]

What is the major difference between the 12 gauge, 16 gauge and 20?

Bore diameter.

 

[Missourian]

Bore diameter in conjunction with chamber length determines maximum shot load capacity.

IOW, the larger the bore, the more shot can be loaded into each shell.

The recognized standard loads are 1 1/8oz for 12 gauge, 1 oz for 16 gauge, and 7/8 oz for 20 gauge.


Example. A 12 gauge #7.5 shot, 2.75 inch standard load is 394 pellets. A 16 gauge is 350 pellets and a 20 gauge is 306 pellets...link.

The SIZE of the downrange pattern will be approximately the same, but the number of pellets shot from a 12 gauge is almost one third greater than the 20 gauge.

Now, if you are not confused enough already, felt recoil is NOT simply a function of gauge. Recoil is a function of gauge + firearm frame + firearm weight plus shell load.

A four pound 20 gauge with likely kick harder than an eight pound 12 gauge.

A 3.5 inch magnum nitro express #4 shot 20 gauge will kick harder than a 2.75 inch #4 shot 12 gauge.

This will get you started, but there's much more to know about shotguns and shell loads. I recommend perusing Chuck Hawks site...starting here...12 Gauge

 

[whitehall]

It's all tradition. Calibers are equally confusing. The .38 is the same bore size as the .357.

 

[ELITEofWarman8]

Ok, this is helpful! Thanks guys!