Question about wind for you 22 savvy shooters
I have been getting into 22lr shooting more now that my kids are growing up and showing an interest in shooting with dad and mom. My daughter is running a Sako Quad with an Athlon Midas TAC with APRS3 reticle, and I just got a CZ457 MTR in KRG Bravo chassis with some other upgrades and will be using the same model scope as the other rifle. We couldn't load mags fast enough between me and my daughter shooting the quad so it was time for me to get my own precision 22lr rifle.
We are starting to learn from our shooting sessions that when we are shooting in wind, or variable winds, we are having to add elevation or take out elevation depending on how much wind and distance we are shooting. Yesterday we were out and setup a KYL rack at 60yds and when we started shooting, we only had to add .3mil elevation and we were hitting both the 60yd KYL rack and the 80ish yard grizzly silhouette which is about 10cm x 10cm size. A bit later on the wind came up and we had about a 12mph gusting 90deg cross wind left to right, and weren't hitting squat until I started holding higher, around 1.5mils! Wind hold at that point on the 80yd target was almost bang on 1mil. The 60yd KYL rack we could still hit with .5mil elev hold and about .2-.4 wind hold. My question is, is this caused by aerodynamic jump and do those corrections seem like they are in the ballpark for AJ? At 80 yds we were adding upward of 1.2mils elev to hit which seems excessive for it to be caused by AJ, from what I have read on the subject. When the wind calmed back down, we were back at our original .3 elev hold.
We are shooting SK Match Lr ammo and the last time I chrony'd the Sako, it was right at 1100fps. The CZ457 seems like it is a bit faster and actually was affected slightly less but still in that 1mil range. Any ideas?
Thanks for any help.
@orkan I've actually watched this video a couple times and just watched it again to make sure I didn't miss or hear anything wrong. I watched most of your videos and read a bunch of rimfire posts when I started getting serious about rimfire, or I wouldn't even know AJ existed lol. It's nice to have a good explanation and quantifiable data like you did in the video. If I seen right, your results showed upward of about 2" or 5cm of vertical spread at 50yds. Is that correct? One thing I can't really find a good answer on is does this spread get worse the further your target is? I could imagine because the change in trajectory is essentially an angular measurement from 0 so it would only get worse if you haven't accounted for it in the correction. However 1.2mils at 80yds still seems kind of excessive, or maybe not because we are using 50yd zeros for rimfire, not 100yds. Unless anyone can confirm we are in the ballpark of what AJ will cause, maybe best to just keep good records and try to repeat Greg's example to see if we can repeat it and see for ourselves what the values are.
If I seen right, your results showed upward of about 2" or 5cm of vertical spread at 50yds. Is that correct?
No... those outer circles on that target is 1" in diameter. I mention one tenth of a mil of vertical per 10mph as the "rule of thumb". The figures you are mentioning are far greater than anything I've ever seen. That's why its important to work angular, and not linear, when speaking about corrections.
One thing I can't really find a good answer on is does this spread get worse the further your target is?
Not that I've noticed. Angular is angular. Obviously if you are measuring corrections linearly, then yes... it will be monstrously larger at distance. That's why you shouldn't work with linear offsets. Only angular. Aerodynamic jump will most definitely not eclipse your wind hold. You describe 1.5 mils of vertical, with a 1 mil horizontal. That's not something I can imagine happening unless you had wind coming extremely hard up or down angle. Shooting right next to a cliff face or something.
I've got some figuring out to do I guess. We have had this same scenario happen before out on the flat prairie where we were shooting steel at 300m and started with 13.1mil elevation hold with no wind, and when wind came up 90deg from left to right, I had to hold just over 17mil's. Doesn't make sense to have that much vertical drop due to horizontal wind but it's happening so I'll just start keeping record of wind and drop values to see if I'm getting consistency and account for it in my hold overs.
@donnie What twist are you running in the barrel?
@orkan I've never verified but Sako Quad spec is 16.5.