Extreme altitude effect on wind correction- can anyone confirm?

[Cactus kid]

Getting ready for a hunting trip that will be at high elevation (15,000+ feet). Living at sea level, all of my most of my practice will be at basically sea level. I am very aware of altitudes effect on bullet drop. But crunching the numbers on the wind correction it gets kinda odd.

According to applied ballistics and the berger ballistics calculator, the windage correction for the SAME SPEED wind is roughly 1/2 at 15,000 feet vs sea level. Can anyone confirm this is correct?

To elaborate, my gun number is 7mph at sea level. So at 500 yards, a 7 mph cross wind will require a 0.5mil correction. At 15,000 feet, the same 7mph wind requires a 0.25 mil correction.

 

[Formidilosus]

Getting ready for a hunting trip that will be at high elevation (15,000+ feet). Living at sea level, all of my most of my practice will be at basically sea level. I am very aware of altitudes effect on bullet drop. But crunching the numbers on the wind correction it gets kinda odd.

According to applied ballistics and the berger ballistics calculator, the windage correction for the SAME SPEED wind is roughly 1/2 at 15,000 feet vs sea level. Can anyone confirm this is correct?

To elaborate, my gun number is 7mph at sea level. So at 500 yards, a 7 mph cross wind will require a 0.5mil correction. At 15,000 feet, the same 7mph wind requires a 0.25 mil correction.

Yes, change the wind bracket based on density altitude.

For the 6XC I am using right now-

At 0ft DA it’s a 6mph gun-




At 15,000ft DA it’s a 10mph gun-

 

[Cactus kid]

Thanks for the verification. I would have lost money on that bet!

 

[Rob5589]

15k feet, damn. Where you headed?

 

[Reburn]

15k feet, damn. Where you headed?

Getting ready for a hunting trip that will be at high elevation (15,000+ feet).

Same question,
I hope its marco polo.......

 

[Cactus kid]

15k feet, damn. Where you headed?

Same question,
I hope its marco polo.......

Not Marco Polo, I’ll be headed to Nepal

 

[Reburn]

Not Marco Polo, I’ll be headed to Nepal

Blue sheep and tahr are just as cool.

 

[thinhorn_AK]

Not Marco Polo, I’ll be headed to Nepal

What sort of rifle, optics and bullet are you using for this hunt?

 

[Rob5589]

Not Marco Polo, I’ll be headed to Nepal

Definitely has the makings of an epic adventure. Would love to hear all about it afterwards.

 

[Cactus kid]

What sort of rifle, optics and bullet are you using for this hunt?

I’m taking a tikka 6.5 prc, 22” proof barrel, that lives in an XLR chassis. The optic is a NF 4-16x42 atacr

 

[Formidilosus]

I’m taking a tikka 6.5 prc, 22” proof barrel, that lives in an XLR chassis. The optic is a NF 4-16x42 atacr

There’s rust on your bolt!

The horror.

 

[Reburn]

I’m taking a tikka 6.5 prc, 22” proof barrel, that lives in an XLR chassis. The optic is a NF 4-16x42 atacr

Beautiful

Looks like seasoning to me. Must have spilled some after seasoning all the meat that rifle looks like it harvested.

 

[Cactus kid]

There’s rust on your bolt!

The horror.

So much for stainless steel! They do match the deep scratches on the chassis, so that’s a plus.

 

[svivian]

I’m taking a tikka 6.5 prc, 22” proof barrel, that lives in an XLR chassis. The optic is a NF 4-16x42 atacr

Looks like a gun that actually gets used and not a safe queen.

 

[Shraggs]

Yes, change the wind bracket based on density altitude.

For the 6XC I am using right now-

At 0ft DA it’s a 6mph gun-
View attachment 460573



At 15,000ft DA it’s a 10mph gun-

View attachment 460574

Form, 2 questions if I may.

How do you know - or what’s the formula/criteria for modifying wind bracket according to da? Ie, what is a 4 or 5 mph load going to be at X da? It must vary with increasing da correct?

Second why not an adjustment factor in mil or moa for increasing da? Is this more efficient? I’ve played with different da on a 4 mph load and it seems that every 4000 change in da reduce hold by .1 mil past 300 yards.

 

[thinhorn_AK]

I’m taking a tikka 6.5 prc, 22” proof barrel, that lives in an XLR chassis. The optic is a NF 4-16x42 atacr

That’s awesome. Mountain hunting in Asia has always seemed like the pinnacle of hunting to me. I will hunt Marco Polo and blue sheep one day.