WHY doesn't rain cause point of impact to change?
- Thread starter Unlicensed Dremel
- Start date
Brian Pfleuger
Moderator Emeritus
There are videos showing what I described above:
https://www.youtube.com/watch?v=HWSES47YkyM
Obviously, the odds are low and the odds of getting it on camera are lower yet, but both do happen.
https://www.youtube.com/watch?v=HWSES47YkyM
Obviously, the odds are low and the odds of getting it on camera are lower yet, but both do happen.
That "halo" wogpotter refers to is called the "trace" in high power rifle competiton. It's best seen and used in rapid fire matches at 200 and 300 yards when a 20X to 25X spotting scope's placed directly behind and above the shooter in sitting or prone positions.
Each shot's trace was seen going into the target and in conditions when there were enough heat waves (mirage) to blur out bullet holes in the black aiming bull, that trace point into the target showed where the bullet went. After the first two shots were fired and the shooter was reloading, the shooter would call those two shots then the coach would give a sight change or, if both were centered, say "no change; shoot away" or words to that effect. The coach would tell the shooter when his shots went out from center so the shooter could hold off to compensate.
A good example I found online is this one:
https://www.youtube.com/watch?v=2SvrYKahCEc
Look carefully as you can see it coming up from bottom-center in the image then going above the target and starting to arc back down. In real life, the trace is much, much easier to see than that video shows.
Its use was also in the US Army Marksmanship Team's manual on sighting in a 30 caliber magnum at 1000 yards after bore sighting. The rifleman would lay down and shoot a round and the coach watched through a 24X spotting scope. As the trace reached its high point, the coach would give sight adjustments so the trace would appear centered left to right and above the target 2.5 times its size above it as it appeared. That's where those rifles put the trace when zeroed for 1000 yards.
Each shot's trace was seen going into the target and in conditions when there were enough heat waves (mirage) to blur out bullet holes in the black aiming bull, that trace point into the target showed where the bullet went. After the first two shots were fired and the shooter was reloading, the shooter would call those two shots then the coach would give a sight change or, if both were centered, say "no change; shoot away" or words to that effect. The coach would tell the shooter when his shots went out from center so the shooter could hold off to compensate.
A good example I found online is this one:
https://www.youtube.com/watch?v=2SvrYKahCEc
Look carefully as you can see it coming up from bottom-center in the image then going above the target and starting to arc back down. In real life, the trace is much, much easier to see than that video shows.
Its use was also in the US Army Marksmanship Team's manual on sighting in a 30 caliber magnum at 1000 yards after bore sighting. The rifleman would lay down and shoot a round and the coach watched through a 24X spotting scope. As the trace reached its high point, the coach would give sight adjustments so the trace would appear centered left to right and above the target 2.5 times its size above it as it appeared. That's where those rifles put the trace when zeroed for 1000 yards.
I was actually thinking more of the white circular effect that you sometimes see in very high humidity, somewhat similar to the effect seen on aircraft wings. The trace you're thinking of is the pressure distortion. I'm more looking at the one caused by moisture re-condensation in the low pressure area directly behind the projectile.
boltomatic
New member
I would think that the momentum of the bullet is just so much higher than that of a raindrop that there would be no noticeable POI shift.
Its like jumping up and down technically changes the course of the earth's orbit around the sun, but the change is so small that for all practical purposes there is no change.
With bullets, the change is small enough that the inherent inaccuracy of the rifle would mask any effect of rain.
Its like jumping up and down technically changes the course of the earth's orbit around the sun, but the change is so small that for all practical purposes there is no change.
With bullets, the change is small enough that the inherent inaccuracy of the rifle would mask any effect of rain.