Here's a comparison of shotgun gauge size and common uses, with a quick reference shotgun gauge chart.
In this video, Janis Putelis of MeatEater explains the most widely used shotgun gauges and bore diameter size of each shell.
You'l learn more about the names, sizes and typical game animals used for each type of shotgun.
Like many hunters, I started out with a small .410 shotgun as young kid then grew into a 20 gauge. I still remember the day my father gave me my first 12 gauge. It was a big deal.
But shotgun size is not just about "growing into a shotgun." Each shotgun size has its advantages and disadvantages depending on the animal being hunted.
As a general rule, you can use a larger gauge for smaller game. However, selecting shot and choke size is critical. If you use a full choke and large size shot, you can damage the meat on a close shot. If you use a wide open choke with small size shot on a longer range shot, you won't enough power or shot concentration to make an ethical kill.
Choosing shells for bird hunting has its own challenges.
In some cases, you can shoot larger game with smaller gauges but you will usually need a tighter choke. Testing a shot pattern is always advised so you know your maximum range.
Use different ammo for small game so you don't damage the meat. Big game usually requires shotgun slugs. The chart below provides a general breakdown as described in the video.
Shotgun Gauge Size Chart with Bore Diameter Size and Common Use
Of course, selecting a choke is also important. If you expect longer range shots then a full choke is necessary. Close range, smaller game are better with wider chokes. Here's a more detailed explanation of shotgun choke tubes.
I bought my 10-year-old son a 20 gauge semi automatic for turkey season. He'll shoot a full choke and he won't shoot unless I can bring a turkey in close.
But I had some fun this fall using his gun to pick off doves out of a cornfield using an improved cylinder choke. The gun is light and accurate and I was quicker than my heavier 12 gauge.
Downsizing shotgun size can be make a hunt more enjoyable and successful.