I ordered one for the department rifle, it is dead nuts on out to 600, that's all the distance I've had available so far - I will order one for my own 700 in the near future. Thank Heaven for things that work without batteries.........
Went to look up the armorer school, discovered it was on July 17th..........Hate getting old. Didn't have any tubing around, so I made mine out of a cut-off 30 Carbine empty brass.