2 7/8's inch or 3 1/2" ?
Elmer Keith did extensive testing with both length Ten's from Ithaca in the new Super_X loads. He was in communication with Askins and other ballistic development folks, as well as the factory. The report that I remember was in Shotguns by Kieth, where the details may be found..
So far as the 2 7/8" Super Ten in comparing to 3" 12, Keith gave the Super Ten 2 7/8" a few more percentage points in patterning efficiency, but declared little field difference.
With the 3 1/2", he did some very good long range work, on those riverine corridor, flight paths where the birds essentially are flying a predictable course, at a regular speed, all season long. Imagine a invisibly-walled, tubular bird superhighway laid out as neatly as a modern freeway.
The distances and speeds and courses are very well known to the gunner and thus leads and allowances can be established neatly as tho the fowl were mechanical ones in a shooting gallery. For people unfamiliar with his Idaho venues, the distance of some shots just seemed like Western braggadacio.
The reports were judged by people unfamiliar with the conditions and shooting, much the same as folks who have never sat down with a good pistol and a couple of cases of ammo out in a Western, county-sized firing range with a mountain for a backstop couldn't conceive of a pistol as other than a short range instrument. In truth, it is NO trick for a novice to learn to lob heavy slugs onto boulders at hundreds of yards, when one can observe the heavy slug strike in the dust.
As to whether the other contemporary makers were able to 'choke' better for a particular load than Ithaca, perhaps some readers here with more familiarity in that literature may report in.
