Nice charts. Yes gun effectiveness is an issue different from, yet closely related to my question. I did not intend to go deeper into this because of the difference, but I am happy to go on since someone mentioned this, and I will edit the thread title.
This is the best article on this issue I found:
http://www.quarry.nildram.co.uk/WW2guneffect.htm
It seems that your effectiveness chart is also taken from the article.
This is a really good article but there seems to be some bias in the “belting pattern” of gun power calculations.
In “TABLE 1: CARTRIDGE DESTRUCTIVENESS” note that the power calculated for hispano mk ii and MG151/20 are both 200. BUT the power of hispano is calculated based on HE shells only, while that of mg151/20 is calculated averaging “API / HET / HE(M)”.
None of these "belting pattern" is historical: “// APIT - HE - HE - MG – MG” for mg151/20 and “// HET - AP - HE - AP” for hispano. Btw, there are debates on actual historical mg151/20 belting pattern, and I am not sure which is correct.
This gun power value is highly depend on belting pattern, or ammo type, as HE shells tends to have higher power, and the far more powerful mine shell further complicates the issue. Simply put, higher HE ratio, more power. Higher mine shells, even more power.
So probably it is a better choice to calculate gun power based on historical belting patterns. And anyway, the calculation in the above mentioned article seem to overestimated power of hispano relative to mg151/20 by a “all HE” vs “API / HET / HE(M)” “belting patterns”.