How do you calculate %xHKO?

After about 25 hits though, the uniform distribution on the dice rolls/rng which used to look like this:

 Spoiler

becomes a normal distribution like so:

 Spoiler

This second one CAN be calculated. But only if we're talking about you taking 25 hits or more in the first place.

This would just barely a bit to calculate %4hko with something like savage blow since it hits 6 times.

I doubt most of you who use 4 hits skills would want to train on something that takes you 6 skill uses to kill. So it's pointless to look at a normal distribution.

The problem with your approach is that it's not dynamic at all. After three hits, that square looks horribly disfigured. And after 100 hits, even though it looks a lot like a bell curve, it's still not exactly a bell curve. It's just a square wearing the bell curve over itself and you'll still be able to see the corners, if only slightly. So your approach should be a shape that can transform with by using the x hits variable, not a static one.

EDIT: Here's what I did.

 Spoiler

Key
max = maxHitPerBullet-minHitPerBullet
avg = averageHitPerBullet-minHitPerBullet
dpb = (monsterHP/numberOfHits)-minHitPerBullet
hits = Number of hits the attack does. Cannon does 4 at max level.
atkNum = The number of hits you've done before this. If this is my third Cannon, than this number would be 3.

If(dpb/avg<1)
=(dpb/avg)^(hits*atkNum)*(dpb/max)

If(dpb/avg>=1)
=1-(2-dpb/avg)^(hits*atkNum)*(dpb/max)

And here's what I did as listed in my spreadsheet. It's a little more complex because it all has to be in one line, and I used different variables than above because I'm ripping this from when I posted it earlier in my Corsair Calc thread.

 Spoiler

Key
hits = The number of hits the attack does. For example, Burst Fire is always 3.
attacks = The number of the attack on the monster. If you've hit the monster once already this is your second attack, so it would be 2.
b10 = monsterHP/(hits*attacks)
All references to damage are the min, max, and average damage for that skill, not from your damage range.

=IF(minDmg*hits*attacks<monsterHP; IF(maxDmg*hits*attacks>=monsterHP; IF((B10-minDmg)/(avgDmg-minDmg)<1; 1-(((B10-minDmg)/(avgDmg-minDmg))^(hits*attacks-1))*(B10-minDmg)/(maxDmg-minDmg); ((1-((B10-minDmg)/(avgDmg-minDmg)-1))^(hits*attacks-1))*(B10-minDmg)/(maxDmg-minDmg));0);1)