First, make sure that no part of your hand is contacting the button when you shoot. It is a small grip and the gun tends to jump around when it goes off. Sometimes, it is hard to tell that you are hitting it. If you suspect, or find this to be the case, you can file the button down a bit. It doesn't need to stick up that far. Apply some tape around the button to protect the grip and fire, file, fire, file incrementally until you get there. Also, if you are using one, sometimes the hooked mag extensions can put added downward pressure on the catch.