I do not know what the standard load for a 10ga ML was. For many years standard for the 10ga breech loaders was 1oz shot with up to 5 drams powder. W W Greener stated the powder charges used in the 10 were all out of proportion for the 1oz shot load used.
he further added the 12 would handle 1oz as efficiently as the 10 & any advantage the 10 held over the 12 was obtained only by use of a heavier shot load. He particularly recommended a 1oz shot load with 4 drams powder.

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