I finally got down to work on the Rex. My plans are to beef up its arsenal a bit. The first to go is probably the original Railgun. I replaced it with this blaster I bought from Japan last year, an add-on weapon for Armored Core mechas. Mixed and matched with a few Kotobukiya MSG parts to get what I wanted.
Rex with stock weapons
The barrel of the cannon can be folded into two parts and then unfolded to reveal a BFG! Nifty stuff! Should have bought more when I had the chance!