I also shot factory shells that were shorter than the box noted. These were Fiocchi dove and quail that actually measured 2-5/8" In fact, I reload them as 2-5/8 inch shells. When I first went to reload them I noticed my crimp would not fold correctly...because the cases were short!

My reloads are light 7/8 ounce shot that I use in several 16 gauges, including two with 2-1/2" chambers.

I have never found cases that were longer than specified by the manufacturer.