Could the barrel be heating enough to give you that much barrel heat mirage on the third shot ?
I learned the effects of a close heat source 20 yrs ago while chronographing loads for my 223 100 yd target rifle. One morning early, I had a problem with the chrono picking up my shots, so I plugged the light system in. Of course, the chrono started reading velocities just fine with the extra light. After about 20 minutes of firing, my groups jumped from from the very consistent .10s-.20s for 5 shots to strings measuring over an inch ! I had also noticed the crosshairs dancing around, but the outside conditions were near perfect, overcast and stabile temps in the 60s . Light bulb came on (in my head), turned light bulbs off ( on the chrono) and the strings turned back into tiny holes again. Just a thought.
I learned the effects of a close heat source 20 yrs ago while chronographing loads for my 223 100 yd target rifle. One morning early, I had a problem with the chrono picking up my shots, so I plugged the light system in. Of course, the chrono started reading velocities just fine with the extra light. After about 20 minutes of firing, my groups jumped from from the very consistent .10s-.20s for 5 shots to strings measuring over an inch ! I had also noticed the crosshairs dancing around, but the outside conditions were near perfect, overcast and stabile temps in the 60s . Light bulb came on (in my head), turned light bulbs off ( on the chrono) and the strings turned back into tiny holes again. Just a thought.
!!! No more new Browning's for me. Thanks to all that replied with suggestions.!!
