Rifle at altitude question

[Engineguy852]

I’ve researched this a little but I’d like to get some opinions. I’m taking a 28 nosler (that I sighted in at sea level) to Colorado where it will be shot around 6500 feet. I will check it when I get there but I’m curious what you would expect? Will it be off a couple inches? Will it be zeroed? Does the muzzle velocity affect how much the altitude changes trajectory? This is all assuming the airlines don’t knock my scope completely off. Thanks for the input in advance!

 

[jpcoll01]

Are you dialing and looking to shoot a long way? If not I wouldn't expect any noticeable difference in your zero (at 100 or 200 yds). I have run the numbers for mine even at distance and it is a small difference, I do update my Hornady app to whatever location I am at but don't change zero.

 

[Engineguy852]

Are you dialing and looking to shoot a long way? If not I wouldn't expect any noticeable difference in your zero (at 100 or 200 yds). I have run the numbers for mine even at distance and it is a small difference, I do update my Hornady app to whatever location I am at but don't change zero.

Awesome thank you! No I don’t plan on shooting farther than 300 yards for this hunt. I’m running the sig bdx system so I may just change the altitude in my app and it should calibrate for the small difference

 

[Sheltowee]

You'll want to plug in the specifics for the the particular load you are shooting, but the Hornady Ballistics Calculator shows a difference of only 1/10 of an inch at 200 yards using the 160 grain Accubond factory load:



Gap opens slightly as your extend range, as you would expect, but difference at 700 yards is less than 7 inches. You are much more likely to have a zero shift due to the scope getting jostled around in transit than the altitude shift, so your idea to check zero upon arrival is still a very good one.

I'll add though-- your body will almost certainly have a much harder time adapting to altitude than your rifle. I moved to Colorado from about 200ft. above sea level. Drink lots of water, anticipate your endurance being considerably less for the first couple of days and, if at all possible, try to get out here a day or two before your hunt in order to acclimate.

 

[Wind Gypsy]

Zero at 100 yards and you're fine. I'd be more worried about being screwed by trusting that bdx system.

 

[Engineguy852]

You'll want to plug in the specifics for the the particular load you are shooting, but the Hornady Ballistics Calculator shows a difference of only 1/10 of an inch at 200 yards using the 160 grain Accubond factory load:
View attachment 286711
View attachment 286712

Gap opens slightly as your extend range, as you would expect, but difference at 700 yards is less than 7 inches. You are much more likely to have a zero shift due to the scope getting jostled around in transit than the altitude shift, so your idea to check zero upon arrival is still a very good one.

I'll add though-- your body will almost certainly have a much harder time adapting to altitude than your rifle. I moved to Colorado from about 200ft. above sea level. Drink lots of water, anticipate your endurance being considerably less for the first couple of days and, if at all possible, try to get out here a day or two before your hunt in order to acclimate.

Yes sir! Thanks for the advice. I was out there last year in the summer and was in the middle of a marathon training block. Think I ran 51 miles that week at 6600 feet and my body seemed to do ok. Now I definitely noticed a difference when we went hiking at got up to 11k, that was wild!

 

[Engineguy852]

Zero at 100 yards and you're fine. I'd be more worried about being screwed by trusting that bdx system.

Yea. A lot of people say that. I’ve been running it for 3 years with no issues, but I understand the worry

 

[winmag]

The difference is minimized with a flat shooting cartridge. I plugged into Ballistic AE, which allows you to use different atmosphere for zero and current conditions. When zeroed at 100 yards, there is no difference in zero between sea level and 6500 feet.

 

[Engineguy852]

The difference is minimized with a flat shooting cartridge. I plugged into Ballistic AE, which allows you to use different atmosphere for zero and current conditions. When zeroed at 100 yards, there is no difference in zero between sea level and 6500 feet.
View attachment 286727

Awesome. I appreciate you all running the numbers!

 

[Addicting]

I’ve never not shot high from sea level to 7000 feet. 1-2” depending on the rifle.

Always rezero!

 

[belshawelk]

I shoot a .28. Just pull the trigger unless you’re way out. BTW I would sight it in at 200 yard 0. It’s what it likes.

 

[Engineguy852]

I shoot a .28. Just pull the trigger unless you’re way out. BTW I would sight it in at 200 yard 0. It’s what it likes.

Yea I plan on it once I get home from this hunt actually

 

[perma]

I’ve been down this road for years. I shoot up as far as 12000’. Don’t rezero JUST for the elevation, rezero for the trip that may have banged up your scope.

 

[Carl]

100 yd zeros shouldn't change, and even at 300 you're talking about 1 scope click of difference between sea level and 10,000 ft. Most people would be well served to check zero after travel as most people don't have bomb proof optic/mount/rifle setups.

 

[jpcoll01]

I’ve never not shot high from sea level to 7000 feet. 1-2” depending on the rifle.

Always rezero!

The ballistics say different, maybe your scope got hit? I have done multiple hunts at altitude and never noticed difference (I live around 400’).

 

[Addicting]

The ballistics say different, maybe your scope got hit? I have done multiple hunts at altitude and never noticed difference (I live around 400’).

Nope, shoots high every trip any rifle.

 

[Addicting]

Here is my story.

I was told it wouldn’t, I trusted and didn’t verify. Missed 2 cows opening day. Went and shot the rifle. 1 1/2 inches high at 200 altitude of 7800. I forgot the .051 Allen needed to rezero the scope. I had a custom dial from Leupold for the elevation.

Everything was so far off on that dial I ended up really screwed up the further I shot with no way to change it.

Next day what should have been a chip shot had me second guessing what to do. Bull was looking back over his shoulder and I made my best guess. Shot was 350ish. Shot just over his shoulder and hit him square in the jaw.

Chased that bull for over two miles before finally killing him.

Dumb mistake compounded by not verifying zero.

Now it’s standard SOP and every time it has to be adjusted coming from sea level.

 

[jpcoll01]

Absolutely need to verify zero for a million things that could have happened during the trip. We agree on that.

 

[step66hen]

Thank All you guys for your input , after watching Randy's latest clip with Nosler expert , he got me nervous and curious . I am planning a trip out west 2024 and the elevation will be between 6500 -9700 and I live and outdoor range shoot at 3100 in western N.C. going to use either my 270 or 308 . I have killed a 5x5 bull and cow with 270 and a Maine bull moose with 308 . I don't shoot over 300yds. Thanks again to All