Have you ever thought about why your second hand does while your primary hand is slowly squeezing the trigger to the rear? Where is your left hand, right handed shooters? What is it doing? I’ll bet it’s pushing your shots off target!
On your pistol, your secondary hand is usually over your firing hand. On your rifle, it’s either on the magwell (like I do), on the handguard, or on the vertical grip (or other device) you installed. I mean, it’s got to go somewhere unless you are awkwardly holding it behind your back.
If you look at the picture, you’ll notice the shots that are all to the right of the target. This shooter was pushing their rifle as the pulled the trigger with their secondary hand. Consciously thinking about making sure you aren’t pushing the rifle or pistol should fix this problem.