Advanced Marksmanship Think I've run into something interesting; shooting between 2 mountains

[TheGerman]

Have been doing a ammo lot testing of certain higher end 22LR rounds and found a spot while I was out hiking/climbing that SEEMED like a great spot, but I may have caught onto its evil intentions.

Assuming I am shooting from south to north, to the east there is a valley that is about 300m wide that then leads up to a mountain/large rock formation that is roughly 200m or so higher than the spot I am shooting is. To the west not 10m away is the ledge to the shelf/plateau I am shooting on that then drops off 100+ feet to pretty much wide openness. Beautiful landscape, just I think its been screwing with me.

My shooting position is facing north and a bit recessed by some of the rock and just the way the land lays. The further north (towards the target) you go, the more any land recesses and it just becomes a true flat spot between the canyon cliff west and the valley/mountain east.

What I THINK has been going on, is that even though at my position (and along the way) I am getting ZERO wind indicators due to there only being either solid rock or heavy/big trees along the way. No real bushes, no high grass, nothing. So unless the wind is going a good 10+MPH, at my shooting position I hear, see nor feel anything. I think relying on mirage here may be key, but with just a desert background this may prove tricky. Anyways, so I start my coarse of fire. 5 x 5 round groups for each ammo and then I come back to it later again as a kind of control. I noticed that I would shoot .6 groups at 100y and then the next would be a 1.2 because of 1 round strung off to the side; or the first shot 2 inches to the side of POI and then rest in 1 small little group. This would happen fairly frequently and it was driving me absolutely crazy because I couldn't seem to explain it and the last thing I thought to blame it on was the wind - because there wasn't any!

My plan is to go somewhere else and redo the testing. MY question is, how likely is it that its the 'hidden' wind screwing? Since thinking of this I remember hearing that shooting between mountains will have all sorts of weird drafts, switching winds and can be fairly unpredictable; I think I've run into this and think mirage is the only way to handle it.

Just seeing if I'm not crazy

 

[ArmaHeavy]

Did you remember about the updrafts, and downdrafts, alternating between night and day?

Even during the day the position of the sun would be a factor, plus with uneven heating on the earth due to the height of the terrain, might be an idea.

 

[TheGerman]

I've been there 3 times, and I started noticing things right off. Like clockwork, at 115ish PM there would be a 'wind storm' for about 25-30 minutes that would then stop afterwards. It would come from both sides (switch) and then just stop after the 30 minutes. 12-20+ MPH nonstop gusts whereas there was nothing noticeable before, and almost at the same time each day.

Normally took out the Kestrel and tried to guess the wind, looked around for wind indicators until it went away. The more I think of it the more crazy shit that probably goes on there.

This canyon/mountain area is crazy as far as shooting a 22LR in.

 

[ArmaHeavy]

Would hiking around your shooting range, and putting up some wind indicators, be out of the question?

 

[TheGerman]

Would hiking around your shooting range, and putting up some wind indicators, be out of the question?

Already ahead of you with a roll of orange surveying tape. I am either going to find a lower spot for the testing portion as I want as few variables as possible, but otherwise was going to hang the tape and see what the deal is.

 

[40xs]

Even when you think there is no wind...there is wind!! It appears from your description of the terrain that what may be affecting your bullet is thermals rising from below, up the draw to the higher peak. These affect centerfire rounds and would have even more affect on .22 bullets. Maybe you could find a flatter terrain to do you testing.

 

[damoncali]

Try some really sensitive wind flags. You can get fiberglass (?) rods (don't know what they're called - but they're meant to be used to mark driveways I think) and surveyors tape at home depot for like $2.50 per flag. Get a bunch, line them up along the bullet's path and watch. Wind does weird stuff. It doesn't take much to push a rimfire.

 

[KPA]

I shoot in the mountains all the time - and wind is the true challenge. You watch the tree tops all along the way, but that doesn't always tell you whats going on between you and the target. Rule of thumb, mornings are calmer than afternoons. Not sure what the secret is to getting a handle on it during the windy part of the day

 

[TheGerman]

Moved spots this week in the mountains. Flat area that is much lower, kind of at the beginning of the mountains rather than up one. I was on the edge of a lakebed that fills with water when it rains and had some water in it and went about 85 yards, the rest was the other side of the bed. Completely flat layout, no weird wind and walked around a bit to see if anything was going on.

Shot the lights out compared to the other spot.

 

[Dan Newberry]

If you're shooting across a valley or hollow, your bullet's flight is taking it through an area that is higher off the ground. The higher off the ground you go, the more the wind blows. (Ask folks who climb towers for a living... 60 feet off the ground on a dead calm day and sometimes you can't even keep your hat on your head for the wind at that level).

David Tubb has a short teaching where he shows a wind flag on the pole barely moving at ground level, and 20 or 25 feet up the pole, the same flag--at the same time--is stood out commensurate with an 8 to 10 mph wind.

Dan