How to Pattern a Shotgun
Woody's answers are based on published federal and state law. Not legal advice. Consult a licensed attorney for your specific situation.
Pattern a shotgun by firing test rounds at paper targets placed 25-40 yards downrange, then count pellet hits within a 30-inch circle to determine pattern density and point of impact.
What This Means for Your Shotgun
Patterning tells you exactly where your shotgun shoots and how tight your patterns run with different loads. This knowledge lets you pick the right choke and ammunition combination for your intended hunting or sporting purpose. Without patterning, you're guessing at your gun's actual performance downrange.
The Detail
Start with clean paper targets at least 40 inches square mounted on a solid backstop. Mark a clear aiming point and fire from a solid rest at your intended hunting distance, typically 25 yards for close cover work or 40 yards for open country shooting. Use the exact ammunition you plan to hunt or compete with since different loads can pattern dramatically differently in the same gun.
After firing, draw a 30-inch circle around the densest part of your pattern and count the pellet holes inside. A full choke should put 70% or more of the pellets in that circle, while improved cylinder might only manage 50-60%. Pay attention to where the pattern centers relative to your point of aim since many shotguns don't shoot exactly where you're looking.
Test multiple choke tubes if you have them, firing at least three shots with each to get a reliable average. Some guns prefer tighter chokes with certain loads while shooting more open patterns with others. The goal is finding the combination that puts the right pellet density on target at your expected shooting distances.
Document your results with notes about choke, load, distance, and weather conditions. Temperature and humidity can affect patterns, especially with plastic wads. A good pattern has even pellet distribution without large gaps where a bird could escape unhit.
Build Impact
Patterning data directly influences your choke tube selection and helps you understand your effective range limits with different loads. This testing prevents poor performance in the field and builds confidence in your equipment setup.