I too, think that I shouldn't need custom grips to shoot decently in double action. I keep thinking, "I must be doing something wrong."
I'm right handed. Right thumb is down against my middle finger tip. Left thumb is right on top of my right, thumb print on thumb nail. Recoil hump down low against the web of my hand, gun pretty well lined up with my forearm, trigger on the first digit.
Everything feels perfectly secure while dry firing, but under recoil the grip jumps down in my hand and rotates clockwise in my hand, both just a trifle but enough to no longer be a solid grip. This change also causes my finger to engage the trigger at a different point.
Could be that I'm not gripping hard enough, but even when I focus on that it doesn't seem to help.
