Well, I figured out that it's not possible to completely remove the P_model weapon from the heavy armor model... or replace it with a blank model, without erasing the P_model for every other model that uses that weapon. I don't even know if that makes sense. But, it does.
The original idea was to have the P_models removed and just have his arm be the guns... but that won't work... so, sticking with my other idea, I've decided to have the weapons latch onto the side of his arm. Here's a screen shot.
P.S. I can't wait to see ppl reskin this model when it's done, I am getting so sick of the green and white color scheme.... ack!