I have tested (many years go) trying to get a double shot pattern by pressing both triggers together on an over/under 12 bore. The patterns were always separated by 1 to 3 feet at 30 yards. That was when trying to pull both at the same time, not just having one go accidently. It is rough on the rear trigger finger. I would expect a double rifle to separate the rounds even further. I held naturally, not too tightly.