OK - I admit it . . . . I have blown away several chronographs . . . . three to be exact. But only one with black powder. And I think I know how to prevent the problem from re-occurring. Biggest issue is with sabot rounds. Even at 30 feet away, a plastic sabot packs enough punch to destroy expensive instruments. I now put a large brick in front of the display area. The steel rods and sunshades are somewhat expendable. You also need to be aware that sometimes the sabot goes through the skyscreens right behind the bullet and gives an odd reading. When shooting conicals there is really no big issue, other than being far enough away to prevent smoke and hot embers from hitting the instrument or giving a false reading.