Is there anyway to change button sensitivity and not just analog sticks?

[AugmentedJustice]

I'm wondering if his is possible, because I'm playing the twin snakes and I find it's impossible to properly lower your gun without firing off a shot due to the lack of sensitivity when pressing/letting go of the the fire button, so I'm wondering if there's a way to bind custom sensitivity to specific buttons etc? thanks

[JMC47]

Twin Snakes doesn't have button sensitivity like MGS2/3 on PS2