A deer is not some sort of super animal. Untill trappers started trapping in the rockies very few guns were bigger than 40 unless produced without rifling. Encounters with grizzlys and buffaloe sparked the demand for large bore guns. There has been a pile of deer killed with a "squirell rifle". A 36 will go through a deers rib or shoulder blade. Just not at 100 yards. If you dont believe me get a 1 inch thick piece of oak. Shoot it at 50 yards. Those old timers could follow a track after a shot and like bow hunters had the sense to sit and let the deer get sick. A rib or shoulder blade is no where near as tough as that piece of oak by the way. Any rifleman capable of hitting a squirell at the top of a tall tree can put a ball into a deers heart, lungs or brain.
Well, that is partially true. And of course this is just an Opinion, all of us have one......
1: The .36 may go thru a shoulderblade if it hits it directly.... but if you do hit it directly in the shoulder with a .36 cal, you will not find the deer most likely, as he will be long gone cause you missed the good part of the kill zone (if not all of it depending on how the deer is standing) especially for a small caliber rifle.
2: Small bore rifles were used back then because of one thing..... the preciousness of the powder & the ball........ Deer hunting was not an option, there were hardly none left to hunt from about the late 1770's till the 1900's. Oh yes, I am sure a feller lucked into one now & then, but if you read books of old times that are about the indians & settlers, it is told many times over they kept pushing west for lots of reasons, but one of the main ones was because they were starving & needed more food. They shot what they had to shoot & what was the most concervative. (small bores) There was no concern of how humane it killed the deer of how long it took them to die. They needed food & used what they had to get them. Believe me, if powder & shot was as easily to obtain athen as it is today, if they were deer hunting they would have used a larger caliber for a sure kill. This was survival, not sport. Another good example is the Buffalo hunters. You think they used a large bore for the fun of it ? No. It was easier, faster, more sure, and it took the buffalo down.......
3: Back then a feller could track a deer fo Miles & Miles........ Because it was the difference of starving & not starving....... 99 out of 100 guys hunting today couldn't track a deer for 50 yards, let alone a mile. Think not ? Listen to the hunters today & the stories of hiow they hit one but lost it........ Thousands of them....... They shoot them with HP rifles & still lose them ! ha ha ! not just now & then but thousands of deer every year.
4: With the choices we have today & the prices available for an assortment of rifles that are so cheap but yet so adequate to deer hunt with, why anyone would even consider using a .36 cal to deer hunt is simply beyond me....... To me that is like going to WV & VA into the mountains to drive all the back roads with a Yugo..... Yes, it may get ya up & down there, but IF it will do it, how safely & how long it takes ya is sure questionable........
Now we can argue all day on the caliber that is adequate to deer hunt with. But ask 100 ML hunters & see what they say. At least 75 out of the hundred are gonna say .50 cal & larger. And of those other 25 they will say a .40 or .45 cal will do it, but then ask them what THEY use & about 15 of thesame guys will tell ya a .50 or .54 or .58. And then you always have a few that just have to try it with no regards to how many they wound (and won't tell ya either) and you will never convince them they need more energy for the kill.......
I am not saying a .36 will not kill one, I am saying there are LOTS of larger & better calibers for doing the job better. And that is exactly why they have laws regulating those calibers.