Pondering this thread's subject has jogged my memory and led to a couple of observations and thoughts.
Moderators, please bear with me as I will be mentioning scoped rifles and sighted bows...
I've been known to hunt early season gray squirrels with an old lever rimfire with a scope. Mostly years ago before my black powder affliction became full blown.
The last few years, I've been using my fowler a lot as my eyes aren't what they used to be.
It's dawned on me tonight that it was, in part, this practice of using a rifle with a sighting system riding high above the bore, that led to my successful use of shooting for horizontal distance.
In my mind, this may make some sense as the projectile is farther from the bore than most of our muzzleloading rifles wearing low sights mostly.
If sighted in at say 50 yards, the bullet may strike as low as 2" below line of sight at say 15 yards.
So, for a shot at a squirrel 30 actual yards away, yet 15 yards away horizontally, I had luck aiming an inch and a half, or so, above the top of its head. The bullet had not reached zero yet.
Similarly, I've shot a lot of 3d archery. Only traditional bows the last ~20 years, but I used sighted compound bows previous to that.
When one anchors those bows, the arrow shaft (similar to the bore of a rifle for this discussion), is inches below the pins (front sight) and your eyeball or string peep (rear sight).
Again, when faced with an uphill or downhill target, I would figure for horizontal distance. While a target may be down a steep hill and actually 30 yards from the shooting stake, I would focus on a tree very near the target, follow the trunk up until I was looking at it "on the level" and use that distance, say 20 yards to choose which pin to use. Sighting on that downhill target, 30 yards away with my bow's 20 yard pin, proved a winning concept.
I know many other archers that sight like this to good effect.
Probably a poor job on my part to convey my thoughts. In more of a nutshell, I'm thinking that the greater the gap between sights and bore...The better aiming for horizontal distance, at angled targets, works.
I do know one thing for sure. Taking squirrels, regardless of different angles, with the Skychief shotload, does away with a lot of this comp-u-tating! :haha:
Best regards, Skychief