Hi icecreamslick
I was going to fill in the hole from the firing warning LED, but the new barrel is too small to accommodate the TBU emitter, so I placed it in the existing hole.
You have pretty much everything that I have/want to do (& a bit more) to my HL Panzer III, so I'm interested in your progress. If you can send a close-up of the TBU emitter LED, & one of its plug, I'm confident I can make one that will fit in to that barrel.
Re the recoil, where is that thread?
Yours Simon M.