What is the purpose of a choke tube for a shotgun?

A shotgun doesn't fire just one cingular bullet as you may know, it shoots a volley of shot, which are basically little BB's. The function of the choke tube is to control the spraying pattern of that shot when it comes out of the barrell. It's kinda like a garden hose nozzle, you can have it more open for say pheasant hunting where you want a more open spray pattern and can afford a little less range. Or you can tighten the spray pattern to increase the range, for something like goose hunting where they are usually pretty high up in the air.

Purpose Of Shotgun Choke

Choke tubes are small tubular shaped objects that screw into a Shotgun barrel's open end. (They come in several other types)Different sizes of choke tubes control the density of shotgun shot patterns to be used in specific hunting situations. The choke tubes compress the shot by directing the shot patterns together rather than letting them spread widely apart over a short distance. By keeping the shot patterns tighter together, the pattern of shot becomes more dense and effective as the range gets further and further away. The more dense the pattern, the more effective it will be shoot at longer distances..

Example: A shotgun without a Choke might shoot a pattern of shot that is 3 feet in diameter at 50 feet, but with a barrel "Choke" tube installed, the same shot pattern might only be 18" inches diameter at the same 50" distance.

I hope this answer/explanation makes it easier for you to understand the concept....

A choke tube restricts the shot from spreading wherever it wants when it exits the barrel. When it passes through the choke tube, it squezzes it all in and makes it a tighter pattern. Different chokes = different patterns.

To keep the pattern of the BB's in a tight pattern or broader & not so closely together so you can shoot at game or targets at closer or further ranges depending on what choke or chokes you have on the Shotgun.*

The purpose is to CONSTRICT or OPEN the pattern of the shot at a given hunting distance.

it changes the pattern, a full choke is the tightest while an open is the loosest.

to narrow down the spread of pellet spay

keeps the pellets inside the shell in a tighter shot group so it takes a longer distance for them to disperse