Altitude's Effect On Trajectory

T

Togwotee

Long Time Member
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Anyone have a source to track the effect of altitude on trajectory ? I'm looking for an excuse for missing my WY ram the first shot last week.

My 300 win mag with a Leupold CDS is dead on down here at home at 3100 feet elevation with a 6000' elevation turret. but I shot over my ram at 420 yeards the first time at 11,250 feet elevation.


I held low on the chest and centered him so it all ended well but I'm wondering if elevation could have made the miss or if I just screwed up ?













Stay Thirsty My Friends
 
Send me the BC, weight and velocity of your load and I'll run it for you.

I have my "settings" calculated for 4500' for home and 11000' for the sheep mountains. It makes a difference but I'm not sure it makes enough difference to shoot clear over the back at such a close shot. We'll know soon enough so just get the info to me. PM, post, text or email.

By the way, CONGRATULATIONS, Dean, on taking your ram. I can't wait to see the pics and hear the rest of the story!

Well done, sheep hunter!
Zeke
 
You can run the numbers through jbm and change elevation. From 3000 to 11000 at 420 yards the difference could be significant. Did you rezero at the higher elevation?What bullet and velocity are you running?

There are other factors to consider also such as the angle of the shot and were you using a rangefinder that compensates for angle.

Congrats on the ram!!
 
I just looked at the POI difference between my round at 425 yards at 4500' and the same round and hold at 10000' and it's less than an inch difference.

I doubt subtracting 1400' from the lower altitude and adding 1250' to the top end altitude would still make a difference of over an inch or so...maybe two but not more.

What was your rifle resting on when you shot? A hard surface will throw me off way more than altitude!

Zeke
 
I was shooting a 30 cal 165 gr Accubond at 3280 fps. I have Swarovski EL Range binocs so the angle was compensated.

I was just using a backpack for a rest leaning down hill a bit so it wasn't a perfect but I felt it was pretty solid.

Doesn't sound like I found an excuse maybe it was just bad shooting. before I hunt with the rifle again I better recheck it , but it's never canged on me before.

Kyle I'll get you some pics I don't know how to post them. he's in the same class as your ram if I'm looking at your pictures correctly. the bio who plugged him said he's 10 1/2 years old and I thought he was 9 1/2 so I didn't argue. he's no booner but I'm tickled as I can be as I'm sure you are too.

WY never lets me down.














Stay Thirsty My Friends
 
I'll be happy to post them for you.
Just email them to me (for my viewing pleasure) and tell me which post to put them in or start a post or two somewhere and let me know and I'll post them.

I agree with you about the age! I'm more happy that mine' s at least 9.5 than I am about the score....although that's okay too.
Zeke
 
I'm wondering why 440, a guy that has expounded here on MM on his vast handloading and firearms knowledge, needs to ask the question of altitude and trajectory. Congrats on the ram though. mtmuley
 
LAST EDITED ON Sep-09-15 AT 10:09PM (MST)[p]I wasn't asking if altitude had an effect I asked how much. do you carry that information in your pocket or do you just remember it ? my shots at double my normal atltitude are so limited I've found I can put that brain storage to better use.


From your comments you might be best off to do the same.



Zeke sounds like you beat me by 3/8 ". that metal tape just wouldn't strech anymore.




















Stay Thirsty My Friends
 
Geez 440, I just found it interesting you couldn't find a ballistics program. Some guys brains have more storage I guess. mtmuley
 
I don't do ballistics programs I leave that to Leupold and Gunwerks . I asked if someone else did and Zeke gave me the answer. I have charts for drop and windage but they don't take altitude into account.

As usual your input was most helpful.

















Stay Thirsty My Friends
 
LAST EDITED ON Sep-10-15 AT 09:32AM (MST)[p]
Dean. High altitude effects the shot for several reasons. 1) the air is thinner therefore it creates less resistance on the bullets trajectory. Yes air creates friction and helps slow a bullet in it's path. In most case it's not enough to matter but from 4000 to 11000 it matters.
2) If you're shooting a heavy charge in the case with higher pressures that can also make a difference. Faster bullets drop less but max loads and high altitude don't always work well together. You breathe more at high altitude because you are working harder to find air......Oxygen matters. Sub zero temps also matter but I doubt you encountered that.

3) if you were shooting at an angle at your ram ( most likely) it made a difference in how the bullets trajectory was effected to some extent. Bullets drop less at more severe angles shooting uphill or down. Higher altitude cause bullets to drop less and it may have made the difference in your shot if you dialed in your shot. Remember your values were calculated where you shot them.

So the combination of all these factors and a couple of others may help explain what may have happened. High altitude effects everything even the shooter. In most cases it's not enough to pose problems for most of us but it can make a difference in some cases.

Only you know what happened with the first shot but if you compensated on the second it made the difference. There's a reason why the military doesn't shoot max loads because in their testing they found that more consistent burn rates and velocity were beneficial to accuracy and scope adjustments in all theatres of operation.

Congrats on your ram!! Your experience paid off since you kept your wits about you and filled your tag so in the end you compensated enough to make it work no matter what happened.
 
440,
I ran the calculations a couple times to make sure and even with the extreme altitude change from 3100' to 11250' it only changes the POI at 425 yards by 1.1"

These calculations are based off a 300 yard zero and the temperature being about the same. If it was warmer in the valley, the POI change would be even less since warm air is less dense.

Boskee is right, the angle of departure will have a much larger affect than altitude..... but some of the rest of what he said was irrelevant and so much smoke laced with a dose of wives-tales. IMHO

Zeke
 
LAST EDITED ON Sep-10-15 AT 11:01AM (MST)[p]Zeke those wives tales you want to exploit may have more relevance in trajectory than a little guy like you may want to believe. But then again I'll bet you don't have the education to understand just why. It's a combination of factors, and don't think the guys that designed the programs didn't compromise some values in making their formulas. Just remember something that effects trajectory at 50 yards is less of a factor than it is at 1760 to 5000- 10,000 yards or beyond........that's why long range shooters want to dial in their shots......... The conditions in which the shot is made always effect the shot like it or not it's true and you can try to disprove that but if it wasn't true you wouldn't be depending on a computer to tell you where to aim. It's nice to know you gave me partial credit but don't really understand the material in it's purest form. Think any of those things don't effect long range targeting with other weapons system? If those things didn't matter, why do most good long range shooters prefer to hand load their ammunition to obtain a more consistent result? :^)
 
LAST EDITED ON Sep-10-15 AT 11:05AM (MST)[p]"You had me at hello"
Oh well.

little guy,
Zeke
 
I've been away a while and it's easy to see why at best it's an exercise in futility and a waste of time. adios.
 
Don't do that!
So we don't agree. What else is new?
I just think a carefully worked-up full throttle load for a specific custom rifle is better than a middle of the road military round which is loaded for a mass of "weapons" regardless of "oxygen" levels.
There were no personal attacks levied against you, just a disagreement backed up by experience. Yes, I quoted a ballistic program but didn't have to since I regularly shoot at a variety of distances and elevations.
Disagreement is one of the spices on MM.
Not everyone who has a ballistics background will believe either me or you all the time!
Take that to the bank!
Best,
Zeke
 
LAST EDITED ON Sep-11-15 AT 10:38AM (MST)[p]


Zeke if you knew what most likely happened why didn't you tell him? Your vast experience didn't allow you to account for what 2 posters on this thread knew was most likely the issue all along. You wanted to punch in the figures and tell him it was only a 1" difference. Well since he aimed low he most likely would have hit his target. Instead he missed. See I tried to give him the reasons why and you being so experienced on your computer program couldn't understand the effects of the conditions he most likely was shooting in.

I'll guess that he had to hold or adjust even lower to hit his ram and still shot high wanna bet? So your 1 inch wasn't the deal breaker you thought it was because if he was dead on at 300 given the shot angles and conditions present he most likely still would have shot over him even compensating for the inch. See I went to great lengths to make him feel he made the most out of a bad situation. In effect if his rangefinder didn't account for the angle he was shooting like he was shooting on flat ground. The bullets path is not flat and since he may have been sighted in at 300 it would easily account for him shooting high if the angle was there to allow for it. Him dialing up his scope only raised his trajectory and the path of his bullet. His compensating to aim low was the right move but in effect the shot conditions and dialing up negated that correction and he shot over the ram. He had no way to know exactly what the bullet would do.

One thing I know for certain he was prepared and had shot his weapon but unless they had a range finder that compensated for the angle he was adjusting too much the wrong way. If the angle wasn't there it would fall to other factors. So I offered an explanation of possibly why.... not give him that 1" wasn't the right answer.... remember he still shot over a rams back while aiming low.

I may have given him the wrong answer too given the circumstances but I tried to give him some things to consider and knowing what I know about that cartridge also threw in some other KNOWN & Proven factors for him to consider. You don't need to shoot full throttle loads out of any weapons to make it shoot and that's precisely why the military specifies what ammunition they want the accuracy tests shot with.

I'm not disputing your hand loads work better in many weapon just stating that in many guns it's not necessary. I've seen many a shooting competition won with factory ammo in a capable shooters hands. Let's try to keep the oxygen (air) remark in context because the effects of oxygen, barometric pressure, climate conditions, wind, temperature, and altitude are well proven not VOODOO.

Congrats to you on your ram as well It looks like both of you had a great hunt. The results speak for both of you with a couple of fine rams.
 
Well done! You're almost there.

If you mean "air density" instead of oxygen and if you mean "drag" instead of friction and if you understand that altitude, temperature and barometric pressure can be rolled into one thing "air density" and if you understand that it's the air density that affects drag, ie; drop, reduced projectile velocity... then we're almost onto something real.

When you spout off about military loads and 5000 yard shots, I can only assume it's puffing and very irrelevant to the question posed my the OP. I guess you know that 1760 yards is a mile... let alone 5000 or 10000 yard shots (maybe a cannon but irrelevant to the topic) and the OP was asking about a paltry 425 yard shot!

You were correct when you initially offered the explanation of angle. Spot on! This affect POI more than folks realize IF the angle is steep enough but he said his RF was "supposed" to compensate for angle. Who knows?

You're also correct about the wind! It's the one BIG variable and all the "text book" learning won't teach a guy how to "dope".

You forgot "spin-drift" in your irrelevant discussion about 1000+ shots. You also forgot the coriolis effect!


Keep up the good work.... and work on your nomenclature while researching exterior ballistics a little more, then put it into practice.

Zeke
 
Zeke I could have easily gone into trig formulas and better terminology but we need to try to write things for guys to understand on here. So while you're busy attempting to clear up my vocabulary (good luck with that) the one clear fact remains you didn't give him an explanation you gave him what he asked for and in the equation it most likely was immaterial as I may or may not have pointed out.

I don't need to work on my nomenclature Zeke I'm retired and managed to do that by building and selling weapons systems to the very guys who you claim don't know that military rounds aren't accurate out of their weapons.

I'm sure they'll listen to you Zeke since you seem to be on the cutting edge...... build a few guns and lets see if you can do the same then we'll see who talks the talk and who walks the walk. My guess is you'll be talking with empty pockets but you'll get an a in spelling and vocabulary.
 
Good discussion and welcome back!
By the way, if you were connected with the service, THANK YOU!

PS: my money is always on ME and my pockets are not empty yet! ha

Zeke
 
Great vid big John!
I've enjoyed that one before and I love the way he points out that everything is exacerbated at long range (1000+) yards.
That kid can shoot too! Some guys have it and some don't.
Zeke
 
>Good! Because a guy can always
>use another sheep tag! :^)
>


I fear it might be one on the last sheep hunts where the tag is in MY pocket!
At my age, these darn backpack hunts are getting tougher and my wife reminds me often that I'm far from a spring chicken!!!! ....not to mention drawing a tag takes decades and I don't have too many more! Oh well, it's been a magical ride!
There's alway rifle shooting and I'll be back out tomorrow and Monday!
Zeke
 
I'm just thinking out loud but what about the OP zero height? If he zeroed the turret at 3000 and didn't adjust for the 11000 ft elevation and rezero it then his turret could be off more than just 1" POI especially since he is using a cds system. I know it's only a 425 yard shot so again I still think it was the angle of the shot or even a mistake in the range reading.
 
Good thoughts Ca.
He has a 6000' turret on his scope but I don't know at what range he was "zeroed". He said he was "on" at 3100' elevation but he didn't disclose the range.
I'm sure 440 was a bit surprised since he seems pretty used to one and done and I know he did his homework and practical shooting.
Damn good thing he kept his cool. Lots of guys fall apart after a miss! I see it all the time in the field, on the rifle range and during skeet competition. The next shot fired, after a miss, is the toughest shot a guy will ever take.
Zeke
 
The shot was a little down hill but my Swarovski rangefinder compensated for the angle. I'm zeroed at 100 yards and I can hit the gongs to 600 yards with extreme consistancy at the 3100 foot elevation my range is at, though my turret is for 6000'.

I need to go check my zero again, it may be high for some reason. I shot at a rock at 350 yards the day before season just to check things out and both shots were a few inches high. I discounted it as to just having a poor rest. knowing this made the correction to shoot lower faster and easier .


There is a lot of room around a sheep even at 415 yards when he's moving around from rock to rock and I had to wait and follow him for the right shot. so I didn't have time to get the perfect rest even though it felt pretty good. I hate to admit it but it seems I just plain missed.
















Stay Thirsty My Friends
 
440,
There IS a helluva lot of planet earth around a ram at 415!
That's a long poke and my "paltry" comment wasn't meant to diminish the distance.
I'm so glad you got it done! Like I said, the toughest shot in the world is the one following a miss! Well done bro!

Boskee, thanks for the PM shout. Pretty classy! Thanks.

Zeke
 
It is funny how we've redefined long range these days. it used to be 300 yards was long range hunting but with the equipment we have today most hunters don't think anything about shots under 500 yards.

But you still have to hold the crosshairs steady.
















Stay Thirsty My Friends
 
The important thing is you kept your wits about you and sealed the deal. I know you're in decent shape and did all the prep for your hunt but most of us don't practice shooting at 11,000 ft let alone after climbing up to it, and the effects of high altitude increase as we age. So you missed a shot but still managed to capitalize on the opportunity so in the end your experience paid off. There isn't a guy on here that hasn't missed a shot in the field or in competition at one point or another. Like Zeke pointed out it's what we do on the next shot that really counts and you closed the deal. No matter how you want to critique yourself the end result speaks for itself you filled your tag with a nice ram and that goes in the books as a successful hunt.
 
"It is funny how we've redefined long range these days. it used to be 300 yards was long range hunting but with the equipment we have today most hunters don't think anything about shots under 500 yards."


I totally agree! Back in the day before we had rangefinders, we used flatter shooting cartridges and sighted our rifles in a 300 yds to extend the comfortable shooting out to MAYBE 400 yards. It was a guessing game just how far a animal was, nobody could say for sure, but we did the best we could and misses were common.

It hasn't been but the last 10 years or so, for me, that i could line up on a critter out there at 500 yards and comfortably say that i could make that shot. 400 or 500 yds, no matter, that is a heck of a long ways away and it's taken me a lifetime of shooting my irons and knocking critters down to finally feel that those shot are doable.

IMO, the average joe, he ain't got no business taking shots at game over 300 yards. The average guy might be darn lucky to knock down anything past 200 yards in field conditions and that too, is no easy shot for most.

As far as Altitude, i've only taken two animals that were definitely above 10K here recently, both my hits were higher, 4-5", than i intended and i knew the range and had did my homework. I don't know why, i just know that info will be in the processor on top of my shoulders for next time. :)

Joey


"It's all about knowing what your firearms practical limitations are and combining that with your own personal limitations!"
 
TOG....Dean how about some pictures of your high altitude Ram for us to see. Congrats on filling the tag and yea we all have and can miss the first shot or even the second shot before putting the game down for the count...it happens to all of us and wonder what we did wrong.

Brian
http://i44.tinypic.com/es7x8z.jpg[/IMG]
 
Kyle I sent you a few pictures, post them here or your WY sheep post if you want no need to start another thread.

thanks , email is as far as my tech skills go.
















Stay Thirsty My Friends
 
LAST EDITED ON Sep-13-15 AT 07:23PM (MST)[p]I just missed a doe at 60yds this am with an open sighted muzzleloader, off hand. No I didn't leave out a zero! :D. What was your sight picture at the report 440? With the delay in the muzzleloader I didn't follow thru and at the report the front bead was above her. Knew I missed and was lookin for blood I knew didn't exist. Lookin forward to those pics of that ram!
 
No sight picture. 7 lb field ready unbraked 300 win mag with hot loads doesn't stay in place very well.










Stay Thirsty My Friends
 
9152img2866.png


I'm trying to see if this will work to upload Togwotee's pics
 
I think my computer is supposing I'm pirating them and won't let me do it YET.
I'll try something different
 
Helluva ram Dean!
Congrats on a fine trophy 10.5 year old brute!
Your's would have scored higher with that 3" extra that was broomed off but the brooming gives it great character!

7259deanram.jpg


9528deanram1.jpg


7951deanram2.jpg


3639deanram3.jpg


Well done sheep hunter!

Zeke
 
One nice Ram.
I can see why that first shot was a miss. That air is thin up on top. LOL

"I have found if you go the extra mile it's Never crowded".
>[Font][Font color = "green"]Life member of
>the MM green signature club.[font/]
 
LAST EDITED ON Sep-20-15 AT 01:50AM (MST)[p]Do you have a level on your scope? Did you adjust parallax?

If not put a level on, go to the range line up your crosshairs on the target, then cant it a few degrees off..watch how far off target the hairs move..

Then bobble your head around and watch how much parrllax error there is..Unless you have a perfectly repeatable cheek weld,parallax is a very important part of making a LR shot. especially out of odd positions up/down hill where your head is likely in an odd position.

You might also find it eye opening if youd ditch the "custom" turrets and learn the basics.A bunch of little errors compound into misses.JMO
 
I was definetly holding the gun in an an unusual position given the fact I was using 2 packs and shooting downhill a bit. parallax could be a factor. I'm more inclined to think in retrospect I just plain missed though. it can happen.



Without the turret I would have been "about" 15" low at 415 yards and known that, then the guessing game of how high to hold begins. I really can't see how that would have made me shoot better.














Stay Thirsty My Friends
 
Canting your rifle can be a big issue but it makes you either shoot low and right or low and left. Probably not the issue here since you hit high.
Just my 2 cents again,
Zeke
 

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