By John Kleespies
An endless topic of debate amongst load developers and shooters is how many rounds should be fired in test groups. Here’s my $.02 on this topic:
“It depends.”
When it comes to accuracy testing, more often than not, I do 3-shot groups rather than 5-shot groups. Why? Because 3 shots more or less tells me the same thing as 5 shots, but I find them less stressful, which makes them more fun. If you think that’s a nonsense answer, then feel free to shoot your 5-shot groups. I don’t mind… because sometimes I’m in the mood to shoot a 5-shot group, and so that’s what I’ll do.
Why don’t I think it matters that much? Because I’ll ultimately shoot 30+ rounds in total and average them all together. Size wise, 3-shot group average will likely be smaller than the 5-shot group average, but it’ll still give me the data I need as to whether or not I have a successful load or not.
More importantly (to me), whenever I’m shooting test groups, I’m also firing over the chronograph, and I’m actually more concerned with the velocity consistency of the round—which is a scientific measure of the cartridge—versus the consistency that it’s exhibiting on paper… which is a scientific measure of my shooting ability.
Those should be recognized as two different things.
So, are all my groups 3-shot… and sometimes five shots…?
Nope.
I sometimes “shoot groups” that aren’t traditional accuracy groups; rather, they are more like informational or training groups that are using accuracy as a form of measurement. In that case, I’ll do 10-shot groups.
For instance, if I’d like to know how a gun shoots with a hot barrel, I’ll fire a 10-shot group at a relatively fast pace to see if there’s any wandering on the target. I used to have a .223rem that would consistently put the first three bullets of a magazine right smack on top of each other— a zero-MOA tack driver! But… then… the fourth round would be a little high and left, and the fifth round would be even more high and left, and by the time I got to shot number ten, my zero-MOA gun was now a 1.5-MOA gun. In fact, what I was measuring in that test wasn’t the ammunition, but rather the gun… which is good info to know before the impending Zombie Apocalypse!
Sometimes, you need a little volume to identify trends.
When else might I do a ten-shot group? While practicing transitions from one target to the next. Or draws. Or first shot off a fast reload. Or pretty much anything that involves speed or shooting from an unstable position. In instances like these, I’m looking for patterns on the paper, which might tell me if I’m pulling or pushing the sights under stress, rushing or waiting too long to pull the trigger, etc.
Again, here I’m not measuring the cartridge, but rather me, the shooter… which is good information to have.
Here’s an example of the last point: Smoke and Hope in Steel Challenge. With my rifle, I start at the flag (a center start position) and shoot the first target on the right, followed by the second target on the right. If I shoot a single practice run, paint, shoot the next, repaint, etc., I won’t identify trends. By going through 10 runs without resetting the plates, on the other hand, I can analyze what I’m doing. Once upon a time, I found that I consistently shot the first plate on the low left corner and the second plate on the high right corner. In other words, I was rushing the first shot (opening the possibility of a low-left miss) and overswinging on the second shot (opening the possibility of a high right miss). With this knowledge, I was able to adjust my practices and became very successful on this stage.
With the last example, 3-shot groups would not have shown me the trends. If I’d shot larger than 10-shot groups, then the errant shots would have spread out enough to cover the entire plate, potentially hiding the trends.
So, my answer to “how many rounds for group testing” is a solid, “whatever the situation demands.”
