Shooting on warm windy days

[bkondeff]

This is the time of year the sense of urgency builds and free time is short. I have noticed over the past few years of continuous learning and trying to stretch my range, that my worst days are the hotter ones.

I had myself and 3 other rookies out all trying to shoot at ranges up to 400 yards.

200 yards was pretty consistent, but at 400 yards everything really opened up. Went from 1-1.5 moa groups to 3-4 moa groups. All guns are verified .7-1.0 moa.

Temps got into the high 80's, with wind gusting from 4-8mph.

Mirage had the targets dancing pretty good. I've not paid too much attention before to how much affect this really has, but I wanted to ask if it could be a big part of the consistent problems.

I know there are so many variables, but it doesn't make sense the extreme changes from 200 to 400 yards.

Basically we just try and aim for the center of the dancing bull. Guns with magnification over 12x were adjusted for parallax.

I also notice that a few guns with near max loads had maybe 1:4 shots with sticky bolts, but not hammer needed or anything. Would that even effect accuracy, all other things being equal?

Same guns shot consistent sub moa groups the am before when temps maxed to 65deg at 200 yards.

 

[chucknbach]

My groups will open up when it's hot. I don't like load testing when it gets over 80.

When it gets hot make sure your rounds didn't sit in your truck for a few hours, with the windows rolled up and before you shoot them. Been there done that.

 

[Greyfox]

I shoot at a range that has 100, 200, 300, and 500 yard lines. I have seen lots of shooters that shot well at 100/200 decide to move to the longer ranges and have difficulty. While the temperature change you describe might change POI, it should not effect the the change in group size you describe. I have seen shooters overheat their barrel in hot weather and effect accuracy. Gusty wind and and mirage can definitely effect accuracy at 400 yards. A full value 8 mph wind will push a 308 in the 8" range at 400 yards, but that is 2 MOA, not 3-4. The most common issues I have seen when shooters first increase their range, assuming the rifle gave good results at shorter ranges are:

Sight picture/target aqiusition problems, they shoot at a large black bullseye target and shoot too big. Aim small, hit small.

Wind and mirage. Lots of info is available on this. Takes time and practice to master.

They use an unstable rest, or havent refined their shooting skills(trigger, hold, etc.)
which get magnified as the range increases.

They adjust their scope turrets for the longer range with a scope that has faulty adjustment response. They then get into a vicious circle of adjustment and loose concentration and zero.

If a shooter has more than one of the above going on, the accuracy problem compounds itself. It generally takes more than one session, and lots of practice to get good at longer range shooting. IMHO.

 

[royinidaho]

Next time your out there set up the rifle in a solid position and watch the bull dance around the reticle. This will give you an idea of why your group sizes have increased when attempting to hold on the bull.