Ballistics question.

[waterfern]

So I bought a new rifle for elk hunting. It's a tikka t3 lite 7mm Remington magnum. So I sighted it in on Saturday at Chabot for 200 yards at the 100 yard distance, sighting it in at 1.5 high. Cronographed the ammo, and ran a ballistics calculator on the ammo. The elevation at Chabot is about 750 feet. The elevation where I hunt is 11,500 feet. I have the ballistic info for both elevations with the ammo I'm using. The question I have is does it change the ballistic data if I chronoed the ammo at 750 and input 11500 feet as my elevation? Or is the chrono going to read the speed the same out of the barrel at either elevation? I don't have time to range it at my hunting spot as its in Colorado. Hope this makes sense.

[Hunter47]

Waterfern, you are over thinking this. If you were going to hunt past 400 or 500 yards I would say you have to do all this work. Most Elk hunting is less than 300 yards. Put the cross hair in the vital section and squeeze the trigger. Since it's a Tikka lite, it's not a 1,000 yard gun.

[waterfern]

True on the over thinking but I disagree with the long range aspects. I did a long range shoot with the tikka on Sunday just for ****s and giggles, hit a 800 meter shot and 2 on the 900 meter, on the 900 the shots ended up about 6"s apart. I know it was blind luck for the most part, but that being said the energy at 10500 feet still exceeds 1200 flbs. Not that I would take that shot but it's nice to know the tikka can do it.

[Ferrum]

I believe that the muzzle velocity will be exactly the same. The thing that changes is the atmospheric conditions on the bullet once it leaves the barrel.

I am not sure which powder is being used, but temperature will effect muzzle velocity for certain powders.

[jmonte35]

True on the over thinking but I disagree with the long range aspects. I did a long range shoot with the tikka on Sunday just for ****s and giggles, hit a 800 meter shot and 2 on the 900 meter, on the 900 the shots ended up about 6"s apart. I know it was blind luck for the most part, but that being said the energy at 10500 feet still exceeds 1200 flbs. Not that I would take that shot but it's nice to know the tikka can do it.

things will change at elevation. If you're expecting to hit a 800 meter shot with a 10,000 ft elevation change your setting yourself up for failure but it looks like you will be reasonable.

I never like to zero a range using ballistic data. I almost guarantee you will be off at 200 yds. Shoot the range you intend to zero your rifle. You're using a system that will have inherent flaws. Ballistic data is only as good as the information entered and 100 yds and a chrono is not good enough for 4-500 yd shots IMO.

If you intend to stay within 300 I think you'll be set-up for success. Beyond that you are guessing at this point....that's no way to treat an animal. Go shoot the yardage you intend to shoot...especially if it's beyond 300.....then you'll have to factor in elevation changes which are pretty accurate if you have the appropriate data.

So really what will be your max shot? That's the really the question we would need an answer to.

[jmonte35]

I believe that the muzzle velocity will be exactly the same. The thing that changes is the atmospheric conditions on the bullet once it leaves the barrel.

I am not sure which powder is being used, but temperature will effect muzzle velocity for certain powders.

correct.

[BillyGoatCrawler]

The reality is the ambient temperature at which your ammo was when you chronod it and when you will actually fire it in the field will have more of an effect on muzzle velocity than the relevant altitude. That is not to say there won't be a difference. Elevation changes affect the external ballistics more so than significant change on internal ballistics. So the dope your using needs to be different than your range at home.

[BillyGoatCrawler]

I see after the fact that I echod what ferrum said. I'll add this in:
You can be OCD in trying to know all computed ballistic variables. But the reality is you will have bigger variation in your shot pattern from poor wind calls. Your time is better spent shooting in wind. A temp change may cause a few inch variation of your point of impact, but you have to first be real good at reading dynamic winds to even have your point of aim be the correct one.

[huntandski]

I'm with Ferrem. The muzzle velocity is the same but there should be less bullet drop with distance as there is less pressure forcing the bullet down.

I think of it like batting at Coors Stadium. You don't hit the ball any harder, but the ball carries and it's easier to hit home runs.

[Fjold]

You can use the muzzle velocity at 700 feet and then use the ballistic program at 11,000+ feet and it will be close enough out to any normal hunting distance as long as the data that you input is good. A good ballistic calculator will adjust for the change in elevation, that is what it is designed to do.

I do all my ammo testing at 560 feet of elevation and JBM ballistics correctly calculates my drop at 2700 feet of elevation to within 2 inches at 1,000 yards.

I've also used the same data at 7,000 feet of elevation to take coyotes out to 732 yards and prairie dogs out to 799 yards.

[Calif Hunter]

Thinner air at 10,000 feet so less friction/resistance to slow the bullet down. The kill zone on an elk is pretty big so if a good range finder is used and you know the ballistics, it should not be a problem. I limit myself to 500 yards on big game, though I shoot prairie dogs and other varmints much further.