A quick note and update! Subsequent to the gathering of all this data, and unknown to me while writing all this, professionals have been gathering data to the effect that the organic 10% gel and “clear gel” do not perform equally. Here’s perhaps the most easily digested summary:
https://www.policeone.com/police-products/firearms/accessories/ammunition/articles/ballistic-gelatin-comparisons-part-iii-IbjkEYB93TAd5o6J/
tl;dr: shots into the clear gel go further and expand less than in organic gel; and there’s not a known/proven conversion formula.
So I’m adding this to each of the three parts, for clarity (no pun intended):
1. The data used in this study does not distinguish between tests done on organic vs. clear gel.
2. As of this writing, I can’t vouch that *any* of it involved tests on organic gel which was prepared and tested to the level of rigor needed to make a professional study.
3. Because of this, one should not assume that a dot on these charts vs. reference lines of 12-18″ penetration and 50% expansion will correlate to normalized organic gel or to your intended target.
and, also importantly,
4. The correlation between rounds and their relative performance and particularly barrel length vs. performance are still valid. How can this be? This is the saving grace of data science; it takes a higher volume of messy or ‘noisy’ data and through statistical analysis, finds correlations (or at least discards things that are definitely not correlations, disproving the negative hypothesis). Clear cell results #1 and #2 may not correlate 1:1 to flesh but they do correlate to each other.