If it were my gun, I wouldn't worry about it. The mfg's do worse to them, typically. I'm thinking no one wants the liability of being wrong with so many different external factors. One oops & I told ya so.
I'd shoot the sporting clays untill your shoulder hurt.
Some guns me, my brother and dad have run a 5 gallon bucket of reloads through shooting trap.
870 Wingmaster
Browning A-5
Mossberg 930
Browning Gold
I have run a case through my Sx2, which is about 1/2 a 5 gallon bucket.