Maybe someone way better than I am could fire up their Strelok or Chairgun???
By no means I consider myself better than anyone. You used a good approach to getting some information. Sadly, the calculator you use is somewhat dated. And Strelok is woefully inadequate for pellet use. You CAN get great results, but it needs a ton of fiddling.
Chairgun is a bit better, but it still needs a lot of fiddling for it to "get it right". Regardless, since it is an "accepted standard", I used it to generate the trajectory for MY 0.20" cal D54 (the prototype for the 30 made later and therefore with some minor differences). I used a REAL MEASURED BC from PP-Calc, and the input data corresponds to my gun, so we'll address the differences later, for now, study this trajectory:
In case the values in the table are not too "visible" they are as follows:
Now, SOME of you may be wondering how the reticle in this scope plays into this, and the solution is relatively simple.
You have to remember that this inexpensive scope is an SFP scope, which therefore means that the 2 mrads of angular spacing between the cross of the hairs when zeroed at 34 yards and the thick to thin transition at the change of thickness in the bottom when the scope is set to about 9,5X, can easily attain 5.4 mrads with the scope at 3.5, so getting the 5.25 mrads is fairly easy.
It is also possible to set up a mrad verification target and CALIBRATE the magnification of the scope to where YOU need to get the pellet to. Just follow the instructions here:
https://www.ctcustomairguns.com/hectors-airgun-blog/mil-as-in-milliradian Will you be able to detect a rabbit at 100 yards at 3.5X? And then take a killing shot? Dunno, that is up to each shooter. I am sure some would and some cannot, but that's the thing, we are all different.
Would there be better scopes to hunt rabbits at 100 yards? SURE! but the cheapest ones I can think of that I would recommend to anyone start at around $500 and from there there are more than a few that span all the possible budgets all the way to $4,000.
Would I honestly recommend, as a professional gunsmith, someone go hunting rabbits at 100 yards with this scope? No. Because I deal with the "general public" and have to keep to more "traditional forms". But I do know personally a couple of hunters who would be perfectly capable.
Do note that the pellet gets to the 100 yards marker with a tad less than 9½ ft-lbs so, plenty of energy to kill a rabbit.
As for the differences between my gun and the general run of 30, basically it is the powerplant (piston, spring and guide), and that the pellet used here is the JSB Exact at 13.7 grs, not the heavy one.
Again, we are all different and we all need to respect what others prefer.
Hope this answers some of your questions.
Keep well and shoot straight!
HM