I have a double that when I first got it a mate doubled it
and then I did when hunting with it the first time.

Wondered what was wrong with it - then realised the rear trigger shape was such that we both touched it occasionally.

Well, recoil wasn't too bad, the first bullet always hit where aimed and the small delay in the other barrel going off meant the bullet went over the animal.

It was hard on the shoulder but nothing that couldn't be handled.

I would never intentionally double fire a double rifle
as it can take it off the face.