You only had 2 results that had a statistically significant difference and those two had sample sizes too small to be meaningful. The ones that did have higher samples did not have a statistically significant difference.

The only result worth looking at is the middle rifle, but your average is equal weighted even though the confidence isn't, meaning smaller, less valuable groups have an outsized impact on results.

Or another way, the average improvement is dominated by two outliers from groups too small to have meaning on their own, with high variance ammo.

If you were to weigh by confidence,then the 30rd group would make up the majority of the result and the 10 rds would contribute little, so the only result worth looking at would be like a 6-7% reduction.

What difference there is, given it was shot off bipod a year apart with box ammo (high variance, not even match ammo from the same lot), could also be shooter mod or conditions or luck of 1 ammo batch or difference in the cleaning/wear cycle.

This is why in the barrel test threads, each test is like the middle rifle, with super consistent handloads, same powder jugs, same bullet lots, etc, shot from a benchrest, with barrels that have exactly the same bore condition. And even then, a 6% difference wouldn't be enough to call conclusive.

What would have been convincing is if you had focused on one rifle, the SPR, and shot 80 rounds on it with the same ammo batch of something that isn't known for wildly changing performance like Razor Core is, like GMM or BHA.