Try applying a little more pressure with your weak hand. Also, try adjusting your thumb positioning on your strong hand to make room for your weak hand on the gun. My carry weapon is a 1911 and I actually began resting my strong thumb just beside the safety, which freed up nearly the entire weak hand side of the gun. Just started doing that the last time at the range, and started shooting MUCH better double taps and quick-acquisitions.
"When a strong man, fully armed, guards his own palace, his goods are safe."