If any of you happen to have an Armada Leader Class Prime His Large Cannon Fits perfectly into WFC (Generations) Primes Hand or Arm Slot so if your mad WFC Megatrons Plasma Cannon is'nt interchangeable no worries now you can have a big ass cannon for prime to! repaint it if you want to make it fit the paint style of the figure if you want I thought it was neat to share this. (yes that is Armada Leader 1 Minicon (Galavtron Repaint) on the far left)
That's pretty neat, but just looks so over sized in my opinion. Can Optimus look like he's holding it with two hands; that might make it look so much better IMO?
you can move the gun to make it seem like hes steadying (like hes holding it to his chest) it looks better in vehicle mode better than it does in robot mode.
carve it out so you can put the forearm in, and give it some detail, would make a good detached turret
Really, most figures -masters onward share the standard peg system, and even some from before that point. There's always exceptions, but if the TF in question has remotely "normal" hands, its pegholes are probably the right size.