A bunch of FPS rigs I have made over the past few years for animating the first person arms!

payday_rig_ultimate: My top tier rig, full IK, scaled bones, colour coding, and every heisters arms and some of the trickier outfit arms! (2.8+ Only)
payday_rig_basic: Basic rig, for rudimentary importing and exporting. No IK. (2.7+) (alt = 2.8+)
payday_rig_advanced: Basic rig with rudimentary empty based IK. (2.7+) (alt = 2.8+)
payday_rig_advanced_bones: Basic rig with rudimentayr bone based IK. (2.7+) (alt = 2.8+)