pumps
Dependability and reliability in more adverse conditions, and ammo choices.
That said, when I competed I used a SX1 for 12 ga and O/U for the little fellas. Reduced recoil as I often ran 25K rds of 12 ga alone in a year. The O/U was a 3 bbl set, replicates the same gun for different gauges. Same reason folks went to tube sets.
I used the 1 1/8 oz loading of hard shot. I wanted all the pellets and density to work for me.[ I migh need that golden BB if I didnt' do my part] A few folks were trying the 1oz load..."rumors" of loadings for 7/8 oz were going to be popular in a 12 bore.
I have used my SX1, and not had a problem with a variety of weather, and adverse conditions. I can say the same of Beretta 302, 303 and the Rem1100.
My experiences mirrored what Bob Brister wrote. The SX1 was the most reliable semi in all conditions tested with various loads. I happen to think it still is.
We have factory loads we didn't have back then [ my day] . Same for components, powders, wads and such.
Interesting enough somethings that always been true, are still true today.
-A pump gun can be shot as quick as many self shuckers.
-Gun fit, proper fundamentals...etc., lessens recoil and not a problem . Actually pump allows/ aids many on second ..repeat shots.
Dependent on shooter, skills, training gun fit of course.
I used a self shucker for years, I still like to. Reason I did was the competition and the SX1 was a great fit, reliable, and ...err...it is a classic machined made gun.
I'd shoot fun shoots, pump only events. Used model 12s fo rthe same reason. Shot many with a model 37, 870 or 1300 as well.
Gets back to what is the task for the tool at hand. Tool needs to fit user and the user needs to practice/ be familar with tool.
Now a days, I stay with pumps. I don't compete. I like the classic simple, reliable, no ammo dependent shucker.