This would be inside a muzzle brake for Tamiya Pershing and Tiger 1.

The IR LED would be inserted into a tube 3/4 inch long, extra wire soldered to cable length, then mounted at very end of muzzle, with perhaps 1/4 inch of tube sticking out if it could not be made flush.

Then probably liquid tape applied to wires out back of LED. The end of flash unit would follow right behind the LED, hopefully with at least part of the light escaping out the rear openings in the muzzle- and so be seen on firing.

I know the flash gives off quite a kick of high voltage- would there be any issue like this or another problem mounting like this?

Perhaps a minimum separation distance would be...?

Or would the flash overcome the IR beam and mask it from triggering an apple response?