The 1902 16 bore Husky I had, had 2 5/8" chamber actual length.
The factory 2 3/4" 16 bore Federal ammo, was under 2 3/4" and worked just fine in my 2 5/8" chamber. Might have been 2 9/16"? or not.
When fired, the 2 3/4" Federal loads had just barely a slight curl for the last 1/16" of the case, indicating the slightly shorter chamber.