Can be done already, but you need to make a custom weapon and rig, then apply it.
https://forum.game-guru.com/thread/209925?page=2#msg2514780
Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz, 2400 Mhz, 4 Core(s), 4 Logical Processor(s), 8gb RAM, Nvidia gtx660, Windows 7 Pro 64bit