When your looking at old guns, or reproductions of old guns, one of the things to notice is the curve of the butt plate.
The guns made in the 1700s usually had a relative flat butt plate kinda like a shotgun has.
In the early 1800s the butt plates began to have more of a cresent shape, and by the 1850s (and later, on sporting arms) they had very deep curves.
These guns with the deep curves cannot be shot comfortably if you hold them at the joint of your shoulder like you would with a modern gun. Just bringing one of these guns to your shoulder, they will gouge your pectorial muscle. If fired from the shoulder, they may cause large bruses and a lot of pain.
These guns were meant to be fired with the butt of the rifle held slightly outside the arm pit towards the elbow, resting on just the upper arm.
When they are fired, the arm takes the recoil and rotates backwards.
No, I don't know why they did this, but the fashion lasted up until the late 1800s. This includes the cartridge guns some of which had brutish recoil like the .45-120 and the.50-140. :shocking: :shocking: