22LR Density Altitude DOPE changes 100 through 200 yards

[Hellbender]

Vudoo V22 w/ 16.5" bbl, Sparrow suppressor, Vortex AMG 6-24, Atlas bipod and rear bag off bench ( I moved the TARGET to each yardage, gun stayed on bench)
Federal 922A (ie RWS Rifle Match), all same lot, 1085 fps, 28 ES

These were not shot for group size, I tried to shoot all 5 in the same low wind condition, approx. 20-30 seconds for all 5.

Tried to catch sun in about same location each day, late afternoon at my range.

Scope elevation was not touched during entire test, 10 shots were fired at 50 yards before each session to warm bbl. Just moved windage 1/2 mil right and left to keep groups uncluttered (kinda)

Black groups were shot at 52 deg. F, 1000 DA (dated 3-16-19)

Red groups were shot at 70 deg. F, 2000 DA (3-24-19)

Brown groups were shot at 90 deg. F, 3900 DA (5-28-19)

 

[Near miss]

I made a short graph to see how it looks.. It clearly shows the brown starts deviating quite quickly.
It would be great to see same temp but different DA results.
According to BA 1000DA changes BC by around 3%

 

[Hellbender]

I'm going to save this board and try to get 0, 1000, 2000, 3000, 3900, and as high as possible (will do another when it gets to be 100+ degrees this summer).

 

[parsintrensiac]

Thanks for taking the time to put that together.

 

[FromMyColdDeadHand]

I have never been able to figure out the change at 200 with just DA. I'm starting to thing that gun temp, ammo temp and the lube on the bullets temp properties have something to do with it. Maybe even barrel rifling config.

Thanks for adding to the knowledge base.

 

[Mr. Wolf]

Great real world data and thanks for the graph. In Everyday Sniper Podcast, Frank mentions adjusting elevation when DA changes by 1000 (I can't remember by how much) but this would bring DA corrections into the rimfire world.
Thank you and will follow along and contribute where I can.
Cheers,

 

[simpletoms]

Good data. Keep it coming.

 

[Kambaku]

Thanks for your effort. I helps all of us.

 

[squishee]

Thanks for this effort.
Last 3 times at my private range (4900 ASL) in Az my air density has been 5200 to 7600. (winter air density )
I see close to 9000 feet air density in the summer.
A 90 degree day at my range is aprox 8500 air density
I was amazed how it changed in a 2 hour session.