A chronograph is a fantastic tool and especially for anyone who's into hand loading. To hand load without one is a bit like driving a car without a speedometer. An old saying states that there are two kinds of chronograph owners; those who shot theirs up, and those who will. Not long after you buy one do you realize that this is absolutely true.
Since 2003 I have had a Chrony M1 which has endured everything from 22 Long Rifle to the 460 Weatherby Magnum, and it has always delivered speed information thru thick and thin. An acceptable exception was when a friend borrowed it and was offended by the fact that it wouldn't detect bullets in heavy snowfall. On some occasions, it has received strong sunlight directly on the sensors, and then it also protests. Or rather, completely ignoring the bullets passage to the shooter's very big frustration. But when these extremes are avoided, it keeps ticking, on a minimal diet of 9 Volt batteries.
On a few occasions it was close that I joined to the grieving crowd of chronograph owners. A friend and I (commonly known as "the Mold Gunsmith from Fjärås") shot alternately over the Chrony with my TRG-22 in 308 and his Remington 700 based rig chambered by himself in 260 Remington. When the shooting was over and the time had come to pack up the Chrony, the blood in my veins froze to ice. There was a nasty bulge on top of the Chrony and there was paint missing. An interesting detail is that there is no corresponding mark on the rear of the chronograph. The bullet must have hit and then changed course enough to not cause more damage. We were never been able to determine if the bump was caused by a bullet in 6.5 mm or 30 caliber, and would probably need some forensic expert to sort that one out.
A few years later another friend was shooting standing with his Ruger Mini-14 and managed to sway a bullet into one of the diffuser rods (I use the rods without diffusers as orientation help when using a scope set to its lowest magnification). The .224" bullet left a piece of its jacket on the rod and the recess now has a beautiful golden hue of copper, clearly apparent in the picture. Finally, if you inspect the display of the Chrony, you will see quite a number of small holes and cracks. These are likely traces of unburned powder that hit at high speed, and high gas pressure in those cases when the chronograph is placed too close to the muzzle. Reasonable suspects regarding these damages is a couple of my previous rifles in 300 Remington Ultra Magnum and a relatively short-barreled Remington 700 Police in 338 Lapua.
Lately I´ve been somewhat hungry for a Magneto-Speed chronograph, but I have not the heart to abandon my old friend. All these marks have given the Chrony a certain character, and it is now impossible to get rid of it. Not that anyone would want to pay for it, but now it´s worth more to me than when it was new.