There's a lot of discussion around here about using shells of different length than the chamber.
Nobody's ever happy.
The shorter shells may well work, depending on recoil impulse. Try it.
If you have the old spring, that might be the perfect place to start fine tuning it for lighter loads. I've not done it, but maybe chop a turn off the old spring and see if that works.
I would caution you to not just remove the friction piece. That controls the speed of the forward stroke also, and removing it can be hard on the forend wood. I think that's one reason there are so many split ones.
When it comes to 16ga there is good incentive to try 2.5" shell vs. 2&3/4" one and not just because they have bunch of 2.5" game loads around. The short-cased "Euro slug" Vo. 1350fps standard American load Vo. 1600fps. Using Euro slug will spare fillings, shoulder and cheek from a lot of pounding "wear and tear". Interestingly most European 2.5" field loads should work fine in working the action because many are loaded to similar potential as 2&3/4" while allowing to avoid pressure increase when longer shell is fired through shorter chamber. Most American 2.5" specialty game loads probably will not work the action because they were designed to be shot in old guns that may even have twist or damascus barrels. This is kind of analogous to old American made 7x57 and 8x57JS hunting ammo that were loaded to be safe in old surplus clinkers thus establishing faux notion that those calibers were somehow gentle and soft recoiling which in reality they are not.
