# Rifle POI change with altitude/temp



## swampfox (Dec 30, 2014)

So I'm looking at getting a Kenton industries elevation turret for my scope on my .270 win for next season. If you aren't familiar, Kenton will build a turret that is custom to the load you shoot from your rifle. You just give them all the ballistics data for your load, as well as the average environmental conditions where you hunt (such as elevation and temp), and they will build a turret that you just dial the yards of the shot into the turret and you're good to go. So my question is, if I send them the data for say 40 degrees and 8500 ft, but I end up zeroing my rifle at a local range at 4000 ft and 60 degrees, will this have a significant affect on the POI at ranges out to a max of 500 yds? The difference on the ballistic charts between those two conditions at 500 yds is less than two inches, so does this mean that my rifle with a compensating turret would shoot two inches high at 500 yds at 8500 ft if sighted in at 4000 ft? Thanks in advance for the replies, I'm struggling to wrap my brain around how a compensating turret sighted in at the wrong elevation will affect POI.


----------



## Utmuddguy (Aug 25, 2013)

The first chart is 4000' second is 8000' of elevation the difference in the two is less than .5 MOA so the answer to your question is yes at the higher elevation you will shoot a couple of inches high but with a hunting reticle like that in field conditions it will make very little difference. Your more likely to miss due to target angle and wind. In my opinion elevation isn't much of an issue compared to other factors ibut YMMV.

P.S. If you're worried about the .4 MOA order the turret for 6500 feet and split the difference.


----------



## CPAjeff (Dec 20, 2014)

Aaron Davidson of Gunwerks explains how elevation and temperature affect the POI starting at 12:35 on the video here -


----------



## Huge29 (Sep 17, 2007)

This mud guy doesnt know; he was recommending shooting a 7mm-08 under water...too much mercury from all of those ducks I reckon :mrgreen::mrgreen::mrgreen: JK That is a great way to show and great advice from a guy who won't ever disclose his credentials, but ill tell you that he knows a little more than the average bear toting a rifle and then some...:mrgreen:
Ive not heard of this firm and am familiar with how Nikon and Leupold will make them for their own, so will this place make them for any scope?


----------



## LostLouisianian (Oct 11, 2010)

According to our resident PhD (aka Karl) you're an unethical immoral human and hunter if you're using that .270 on anything larger than a cinnamon teal


----------



## Loke (Sep 7, 2007)

In his latest version of ballistic excrement, we were enlightened to the fact that the 270 Winchester is a manly caliber capable of cleanly and ethically harvesting large game animals. It is the 308 and it's descendants that are the moral weaklings that wound and dishonor the noble beasts that we pursue.

Back to the original subject. I suspect that you can't see the 2" difference at 500 yards. It won't matter in the real world.


----------



## LostLouisianian (Oct 11, 2010)

Loke said:


> In his latest version of ballistic excrement .


Dang it loke just as I had a mouthful of hot coffee. Do you know what that feels like coming out of your nose ???? LOL


----------



## KineKilla (Jan 28, 2011)

Loke said:


> In his latest version of ballistic excrement, we were enlightened to the fact that the 270 Winchester is a manly caliber capable of cleanly and ethically harvesting large game animals. It is the 308 and it's descendants that are the moral weaklings that wound and dishonor the noble beasts that we pursue.
> 
> Back to the original subject. I suspect that you can't see the 2" difference at 500 yards. It won't matter in the real world.


...but any projectile weighing less than 200gr can't possibly be a good choice for big game hunting so there is NO WAY a .270 will even come close. Just ask any of the dead animals on my wall and they will tell you that the .270 that killed them was not the right choice.

As for the OP, I'd go with the "split the difference" approach as mentioned. Then I'd practice at those ranges in those conditions so you have little or no surprises when the shots count.

I may be wrong but I think the temperatures will play a bigger role when using certain powders than the elevation will...as long as you practice in the real world conditions I'm betting you'll be fine.


----------



## swampfox (Dec 30, 2014)

Thanks everyone for the replies. Sounds like the difference is small enough not to worry about it, and I think I'll take your advice and split the difference and use 6500 ft. I'm not comfortable shooting out to 500 at the moment anyway, but I'm hoping to put in a lot of rifle time over the spring and summer and get there. And Huge29, they won't make them for every scope necessarily, but they do make them for a wide variety of scopes. Check them out here to see if they make one for your scope: kentonindustries.com

As for the .270 and cinnamon teal, I think it should be enough gun. Maybe not for a fat migrating mallard or canvasback, but if I get a premium bullet like an accubond maybe it will get it done. Actually, I have a guy in our annual deer camp who always says something like "you sure do like those little calibers" or something like that. Funny that a .270 on deer is little now. I own a couple .300 win mags but I hate shooting them. They rattle my brain too much and I don't shoot as well with them. I'll stick to my little gun.


----------



## waspocrew (Nov 26, 2011)

I recently picked up a Leupold VX3i with the CDS turret - once I develop a load that I feel would most likely by my "go to", I'm just going to go with the average conditions for the area I would plan on hunting. Like others have mentioned, the actual difference would likely be pretty small (assuming it wasn't a huge deviation from the actual condition). 

While the custom turret is pretty cool, I think I'll stick with the originals for my other scopes and dial accordingly.


----------



## longbow (Mar 31, 2009)

Elevation and temp does make a difference. No problem though. Let's say your max range is 800 yards. When you get to your hunting spot, take a shot at 400 yards and adjust your turret so it's right on at that distance. You might shoot high/low a bit at 100 out to 800 but it will be negligible.


----------



## wyogoob (Sep 7, 2007)

It's interesting to get in a ballistics program and change the altitude and temperature, even the humidity, values and see how much the ballistics change.

.


----------

