How to get Crit RATE higher?

I am building around Unstable Bomber and am trying to get my Crit RATE up. I am using 4 piece Lone Wolf with Shaman Vulture top, gloves have Crit Boost Mod, pistol calibration has +4.6% and +7.1% and I am sitting at Crit RATE 20%
How can I get a higher Crit RATE?