The way I always zero with any thermal, cut out 2" hole in a target tape a hand warmer behind it, use the one shot zero, fire the shot, keep the cartridge from the shot, heat it up with a blow touch and put it in the hole you have just shot, go back to your gun and use the one shot zero to move the hairs to the now glowing cartridge..
Always worked for me...
Always worked for me...

