September 09, 2013
How To Pattern A Shotgun: Always Count Your Pellets First
By Phil Bourjaily
During the testing for “The Truth About Shotgun Ammo” I learned it’s important to count pellets in a shotshell before you pattern.
Before we patterned any load we took three shells from the box, cut them open and weighed the payloads and counted the pellets. The results were surprising. Weights were consistent but pellet counts were not. Not all pellets of the same size are the same size. Sporting Arms and Ammunition Manufacturer’s Institute (SAAMI) specs allow variations up to .010” in pellets of the same size.
That small difference in size can add up to a lot. For instance, the pellet counts in a 3 ½-inch, 2 ¼ ounce load of 4 shot and a 3-inch, 2-ounce load of 4 shot were almost identical even though the heavier load should have contained about 35 more pellets. Despite that difference, pellets in both boxes of shells were within spec.
Now, a turkey probably won’t know the difference, but if you are counting holes and figuring pattern percentages when you test and compare loads, you have to know how many pellets you’re starting with or your results will be skewed.
Second, because no two patterns are truly alike, it’s important to shoot more than one to see how a load performs. We shot 10 patterns with every shell we tested. We actually started out shooting 25, but decided that after 10 we had reached a statistical point of diminishing returns and it took a lot less time. We had the advantage of an underground, windless tunnel, and endless roll of paper that automatically gave us a clean sheet of paper after every shot, and a computer that could count and tabulate all the holes in a sheet in three minutes. Without those advantages, patterning is a long, boring process. You can get away with shooting three patterns with the same load at a bare minimum to see what it does, but is five is better, 10 is best, more than that doesn’t seem to be necessary.