That's pretty much it . . . when the LED was on top of the barrel and either the cannon was slightly elevated or the tank was sitting on a slight incline in terrain, the barrel was indeed partially blocking the infrared beam from the LED. Putting the LED on the bottom of the barrel eliminates the cannon from getting in the way . . .

It felt great, in a guilty sort of way, as driver of the Sherman, perpetually scoring hits and knocking out the t34! It was, indeed, too good to be true. Since the t34 wasn't registering hits from point blank range, when it was hitting my Sherman from 20 yards out yesterday, sometheing had to be wrong. Popping out the hull and inspecting the turret revealed the problem.

The problem is the stock WSN canon recoil mechanism. Unlike the tamiya unit, the wsn unit uses a constant rotating arm to pull back the cannon. The rotating arm caught some loose wire of the LED unit and chewed it up. Man! This little recoil unit packs some powerful torque. It chewed up the wire so tight that I had to cut the bound wires and pull them out with pliers.

I'm debating installing the LED inside the hull like the Tiger one and not using the external mount. What do you guys think about this? How will affect the performance of the LED? Thank all!