It's spring up here in Wisconsin which means weather from 30 degrees to 70 degrees but often winds of at least 10-15 mph per day.

I went shooting the other day with a gun that has had a problem with vertical stringing. I found a load that works really good at 300 yds.

Usually with sidewinds I get 4" horizontal groups. With no wind I get some pretty nice groups around 3" at 300 yds.

The other day I'm shooting at 300YDS with 10-15 mph winds directly at the rear. I'm shooting out of a shed so maybe some wind comes over the top for a few yards. Anyhow I was getting vertical dispersion again....of about 5". Horizontal was about 2".

Could the wind cause this??? I'm talking 180 tsx out of the 300 wby at about 3220 fps.

WHAT DO YOU BENCHRESTERS SAY??

kraky

A direct tailwind of 10 to 15 mph would not account for that much vertical. A 10 mph wind is only about 15 feet per second and you'll get an extreme spread of a lot more than that from your best handloads.

I suspect that there was some sort of vertical wind element due to terrain or, as you said, the wind coming over the roof of your shooting shed. Vertical deflection from wind is the hardest of all to read - and by hardest I mean damn near impossible.

Ray