Just for the record, I own a Krieghoff .470 NE and have fired several hundred factory loads from it. I practice relentlessly in the months preceding a safari and of course, use the rifle during the actual safari. I ALWAYS fire the rear trigger (left barrel) first. The rifle has NEVER doubled.
First, the rifle has an extended LOP and the rear trigger falls more readily to hand. Second, I am concerned that if my finger slips off the front trigger during recoil, it may bump the rear trigger on it's way back, resulting in an AD.
Personally, I would not own a double rifle that doubled.
My Krieghoff and I have hiked many trails together. It saved my life during an elephant charge in 2010. It prints two Barnes monolithic solids within an inch at 50 yards. I wouldn't trade it for anything, including a best grade London double.
