The notches on choke tubes are used for identification purposes. Each notch corresponds to a different constriction, or degree of tidiness, for the internal bore of the tube. This allows the shooter to quickly and easily select the choke tube that will give them the desired result for their specific game and load.
There are a few different schools of thought on what the notches on choke tubes are for, but the most common explanation is that they help to align the tube with the barrel. Over time, barrels can develop a slight bit of differential wear and tear, which can lead to misalignment between the two. The notches provide a way to ensure that the tube lines up properly with the barrel, which in turn helps to improve accuracy and patterning.
Another explanation is that they serve as vents, allowing gases to escape to prevent strain on the internal components of the shotgun. This can be especially important when using high-powered shells, as the increased pressure can put a lot of stress on the gun.
There are a few different reasons for the notches on choke tubes. One reason is that it allows for better gas seals. Another reason is that it helps to prevent wear on the tube. Lastly, it can help to improve the accuracy of your shot.
When choosing a choke tube, you want to make sure that it has the right constriction for your needs. If you are using a shotgun for hunting, you will want a tighter choke so that you can get a narrower pattern and take Down the game more easily. On the other hand, if you are using your shotgun for skeet shooting, you will want a looser choke so that your pellets spread out more and You have a better chance of hitting targets.