Freund- 40-90 vs 44 & 45 calibers

[Sarge]

Received the book, Freund & Bro. Pioneer Gunmakers To The West, for a Christmas present. In a letter to Sharps Rifle Co., Frank orders a 8 pound octagon barrel in 40 caliber:

'We want this barrel for our new breech mechanism as the 40 caliber does much finer shooting than the 44 and 45 caliber. This is our experience and likewise that of our hunters in this section of the country."

In a subsequent letter, he writes about selling many 45 calibers but when put to the test by those who have used the 40 caliber, they complain that the ball travels too slow, shoots too much lead and requires greater elevation with less accuracy in shooting. Those complaints are not of the few, but of many, and too from hunters.

Can anyone elaborate on what their and their hunters experience was that made the 40-90 superior to the 44 and 45 calibers?

Sarge