I always thought on the barrel would be better because it's what you aim by?
I know the tamiya holder for the IR emitter is a certain depth and size I am thinking with the IR emitter in the mantlet because it's not set back in a pipe a certain distance like the tamiya clip on holder I would guess the IR beam is being wide spread because of the way it sits in the mantlet?
I thought all tamiya tanks used the clip thing?