L
Larry Elliott
Guest
The other day I got out to the range an hour or so earlier than I usually do, got my chronograph set up, and started shooting. The first velocities were around 2000 fps lower than I might have expected. I rechecked the alignment of the screens and their distance below the bore line. Everything seemed to be fine. I changed the battery and noticed no improvement. Baffling. Not being the quickest puppy in the litter I packed things up and came home wondering what had gone wrong with the chronograph.
The more I thought about the problem I remembered having a similar problem maybe 11 or 12 years ago at another range that runs west to east instead of north to south. Chronograph problems were nearly constant there, although the chronograph worked just fine at still another range that ran south to north and had safety baffles overhead which limited light to what was directly overhead. At the west to east facing range I taped cardboard light baffles to the southward glint shield supports and the problems went away completely. Today I went to the range prepared with material to use for baffles, but by the time I got around to shooting the sun had risen high enough so that it wasn't a problem and the shooting and chronographing went well.
For some reason it seems that "sky screens" or maybe just the ones on my chronograph (an old PACT Model 1) are susceptible to light entering from the sides of the screens. Maybe it's just my old screens (another guy was there the previous day with a newer model PACT chronograph that uses screens with a different housing and experiencing no problems at all), but if you happen to be getting strange readouts from your previously reliable instrument, changing batteries doesn't fix the problem, and there's light that's more from the side than directly ahead of or behind the screens try shielding the sunny sides of the screens from the sunlight.
The more I thought about the problem I remembered having a similar problem maybe 11 or 12 years ago at another range that runs west to east instead of north to south. Chronograph problems were nearly constant there, although the chronograph worked just fine at still another range that ran south to north and had safety baffles overhead which limited light to what was directly overhead. At the west to east facing range I taped cardboard light baffles to the southward glint shield supports and the problems went away completely. Today I went to the range prepared with material to use for baffles, but by the time I got around to shooting the sun had risen high enough so that it wasn't a problem and the shooting and chronographing went well.
For some reason it seems that "sky screens" or maybe just the ones on my chronograph (an old PACT Model 1) are susceptible to light entering from the sides of the screens. Maybe it's just my old screens (another guy was there the previous day with a newer model PACT chronograph that uses screens with a different housing and experiencing no problems at all), but if you happen to be getting strange readouts from your previously reliable instrument, changing batteries doesn't fix the problem, and there's light that's more from the side than directly ahead of or behind the screens try shielding the sunny sides of the screens from the sunlight.
)