Well, they're soft lead bullets, after all. None of them survive all the various manufacturing processes without getting a little out of shape. So there's some variance in their shape right out of the box once they're in our hands. Even with Eley's optical comparisons they do in their QA. Here's some example data from the last time I was lot testing some Tenex:
1022-03228
14.75 C
29.9575 inHg
73% humidity
G1
BC standard deviation: 0.00978749261291005
Average BC = 0.13261906075984856
RA4
BC standard deviation: 0.006669047916226526
Average BC = 0.10113845004830294
1022-02294
17.5 C
29.9495 inHg
64% humidity
G1
BC standard deviation: 0.008471375836183561
Average BC = 0.13557324861225312
RA4
BC standard deviation: 0.006045275811618475
Average BC = 0.10385223388671859
1022-02296
21 C
29.9455 inHg
64% humidity
G1
BC standard deviation: 0.011361120100101697
Average BC = 0.12847710609436017
RA4
BC standard deviation: 0.007790074177904101
Average BC = 0.09906054496765121
1022-04336
23.5 C
29.938 inHg
60% humidity
G1
BC standard deviation: 0.012719435340377458
Average BC = 0.1283333104970502
RA4
BC standard deviation: 0.008988165160787376
Average BC = 0.09846845530500299
1022-06176
24.5 C
29.945 inHg
57% humidity
G1
BC standard deviation: 0.011358902750155568
Average BC = 0.12229304677432327
RA4
BC standard deviation: 0.007440265706002491
Average BC = 0.09444457693198277
There are some noticeable differences among all five lot numbers there. There's a good range of difference in their averages, as well as in their standard deviation values. It's a contributor into what we finally see on target. It's not the only thing that matters, and it certainly isn't the only thing that we see variance in, either. Those are calculated from LabRadar data using Labrabaco for both G1, which we really shouldn't be using with 22 LR but still done for curiosity's sake, as well as the RA4 model that we should use for 22 LR. That was taking care to get very good environmental data. There is no doubt that there's a difference between the different lot numbers, as well as a good deal of variance within each lot.
There's another method of getting G1 values that ignores environmental data and it seems to return numbers that really are quite far off from reality, but still aren't bad just for the sake of itself. I only mention it because it makes it easy to generate a lot of data like in this graph for a lot of different data gathered over time. Really, I only look at these ones to see the general shape of the body of data, as the numbers themselves aren't really useful for anything beyond that unless you really don't care about environmental effects, which you should.
As you can see, there's quite a spread in those 100 shots. Each shot has a bunch of data points going from left to right. Each shot's trace of points is somewhere in the vertical spread of the total graph. The data's kind of noisy, but you can still get the general idea of what's going on with all of the shots. Some are obviously better/worse than others, even if you discount some of it just because of how noisy it is. I also looked at some other ammo now and then over time and have a small comparison of those.
The rejected column is the percentage of shots that fell out of Labrabaco's acceptance range. I forget the number it uses off the top of my head at the moment, but that's just when it falls too far away from the average. (I looked it up now. It is anything beyond +/- 2x SD.) I think all the data there is all at least 100 shots, too. One thing this should tell you if you're at all familiar with some of this ammo is that BC alone doesn't tell you much about how it is likely to shoot. The S&B stuff at the bottom has the second best BC SD there, but it's garbage, hehe. Interesting to see how different it was out of my CZ 453 Varmint compared to the Win52 bench gun. I'm not quite sure what to chalk that up to. Those CZ hammer forged barrels are known to be rather tight, so maybe it was just making them more alike as a result of squishing them a bit more. I don't really know. It also has more rejected, so go figure.
So, the BC can differ quite a lot from shot to shot. And that's going to matter more out at 100 yards than it would at 50 yards. I don't think that would be something that would cause something like the flier you saw there all by itself, but it probably plays some part. That, and all the rest of the ammo variance we have to live with in 22 LR.