Can anyone here date these? They're 2 1/2-1-6.

Alcan was a joint project between S&W and Fiocchi. I've never seen their shot shells! But I would GUESS 1970's.

Ivan

I started getting them in the late 60's

I used Alcan shotshell wads reloading 20 ga in 1964 with my Lee loader.

Alcan (E Alton,Illinois) Made shotshells starting in 1951. Also made reloading components, wads, primers empty hulls, ect. They imported smokeless powder and marketed it under their name and a simple number system attached to it.
I still have a good supply of Alcan #5 and #8 that I load occasionally with older data still available.

The short 2 1/2" 16ga shells are probably from the early days production till the early 60's when standard 2 3/4" 16ga loads and chamberings pretty much were the norm in commercial off the rack offerings.
2 3/4" 16ga shells were the USA industry standard earlier on but foreign guns with the shorter chamberings and older US guns still in use kept a demand for the 2 1/2 and 2 9/16" length 16ga shells for quite a while.

'Short 16's' are still commercially loaded in the US by RST and others that cater to the vintage shotgun shooter market. They generally use Cheddite hulls & primers.

I'd say your box is from around the mid-1960s. I have one box of 12 Ga. which is identical, but in a little better condition.

After 1962 as it has a child warning on the box which was standard after that year.