"I am following your Shotgun program, and after 6 weeks I'm in love with it. I do really like the template, and the possibility to choose exercises for the troubleshooting days.
"However I have a question about the shotgun movement of the third day, the bench press. I found that even if I lift a lot less with the dumbbell bench press (52 lbs) than the barbell bench press (132 lbs), my pecs are much more sore the next day with dumbbells.
"Is the dumbbell bench press intense enough to be a shotgun movement? Can it help increase strength (and eventually mass) as much as barbell? I'm working with the format 6x3. Thanks in advance for your input."
My Answer- Yes the dumbbell press performed in a 6x3 format would qualify as a Shotgun movement. Even though you are using less weight on the dumbbell bench press as opposed to the barbell bench press, the dumbbell version is superior for hypertrophy for 2 reasons:
1) There is a greater range of motion with the dumbbell bench press. Whereas the movement stops at the bottom of the bench press when the barbell touches your chest, the weights will go past your chest in the dumbbell version. This will give you a greater stretch in the pecs, and stretching a muscle under high tension (i.e. heavy weight) will induce greater muscular size.
2) Dumbbell movements require greater stabilization from the muscles being worked. In other words, your chest, triceps and stabilizer muscles have to work much harder to move heavy dumbbells in a straight line as opposed to a barbell.
In general, heavy dumbbell movements are superior to barbell movements for hypertrophy for the upper body.