W W Greener, 9th edition pagr 400;
"The most generally useful type of 10-bore is that of 8½ lbs to 9½ lbs in weight & using as the standard charge 4 drams powder with 1½ to 1 3/4 oz of #4 (US#5) or larger size of shot".
Greener was of the opinion the old 10ga load using 5drams of powder behind only 1¼oz was a load totally out of proportion & that any advantage the 10 possesed over the 12 was obtained only if the shot charge exceeded 1¼oz. I tend to agree.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra