You’ll need to think about a variety of considerations to be using the right shotgun cartridge.
The cartridge you use needs to match the length of your shotgun chamber or be smaller. If you use a cartridge with a longer chamber length than your gun you are likely to cause serious damage to your gun and risk injury to yourself. Chamber length is clearly marked on both the cartridge and the cartridge box and shotgun chamber lengths are generally 2 ½, 2¾, or 3 inch (65, 70 and 76mm).
Larger shot will travel further with more energy
Steel shot is legally required for wildfowling
Usually the heavier the gun, the better the recoil is absorbed. Side by sides generally require a lighter load of around 28-30 grams whereas over-and-unders are heavier and can take a cartridge load up to 34 grams.
Apart from your size and legal requirements, what cartridge you shoot with is up to you. Some Shots like an all-round cartridge that gives a comfortable level of recoil, accuracy and shooting style.
Some Guns lean towards No. 5 shot, as the heavier pellet is more likely to kill cleanly, though there are fewer pellets in the killing pattern.
Pigeon shooters sometimes prefer No. 5 shot for pigeon as, again, there is more stopping power and penetration.
The latest riflescopes won’t break the bank and they offer the shooter a wide range of invaluable features, says Andrew McKean