>>5742029912 gauge has lower peak pressure for comparable loads than 16 gauge and there is 76mm chambers for it while 16 gauge only goes to 70mm.
So your typical oldschool 12/65 guns tend to last longer than their 16/65 cousins given they are of the same build quality, while modern 12/76 guns can be fed magnum rounds unavailable for 16 gauge.
For your typical 30g hunting loads, there is no difference between the two.
16gauge ammo can be hard to find, depending on where you are and is ~1€ more per box for many loads.