I started at age 12 in 1964 with a Springfield Arms break-open single-shot 20 gauge (Chicopee Falls Mass, later to be acquired by Savage/Stevens) with no recoil pad. At that time I had no clue about stock fit, but it must have been OK as I had no complaints when shooting it. I certainly agree that when shooting a single-shot shotgun one must make every shot count, and with the scarcity of pheasants in Southern Michigan one never had much of a second chance.
Maybe we were a bit tougher back then, and I never grew over 6' tall even as an adult. When I enlisted in the USAF in 1971 I weighed 142# which was 1# over the minimum for acceptance, so I am not a big guy.
I'll take that 20 gauge gun any day to hunt upland birds. One just has to keep the gun moving.
Jim
Uhh, when I enlisted in the USAF I weight less that 140. No problem with any sort of minimum weight. But, I was a bit shorter 5'8". Maybe it was a height vx weight thing.