A few years back, before the advent of adjustable combs; it was a common practice among some (not all) trap shooters to bend the barrels up. I watched John Storm do it. I watched Bueford Bailey do it.
They used several methods, including putting the gun's barrels between a semi trucks dual tires and bending them up. John Storm had a more sophisticated system, using a vice device he kept with him.
So, yes, it has been done.
Sam Ogle, Lincoln, Ne.

Sam Ogle