Home Forums Hunting & Shooting Ask The Gunwriters .270 trajectory from treestand?

Hi guys, I have a Sako .270 that shoots tite groups inch and a half high at 100 yards with winchester 150gr. ammo. This year I am going to be hunting deer from a treestand 20 feet up and shooting out to possibly 300 yards. What I am wondering is how do you think the 20 foot elevation will affect my bullets point of impact at that range whether it will be lower than on the ground or the same? I would just like to be prepared when a 12 pointer comes out at 300 so I know how to aim differently. Chris.

At 300 yards, the difference in height isn't going to have much effect. If my math is correct, assuming the aim point is three feet off the ground at three hundred yards from a 20 ft elevation, you are talking about just over one degree (1.08 degree) of angle. You wouldn't be able to detect the difference due to that small of an angle, so don't worry about that part of the equation. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" /> Enjoy your hunt, and welcome to the Campfire!

The 2 things I found out about trying to make a long shot from a tree stand is that it's darn hard to do when the wind is blowing the tree back and forth! <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
A handy thing idea that I came up with was to make a loop out of a few feet of rope and toss it over a branch overhead. Running the rifle through the loop and holding the other end with my hand on the forend made a pretty steady rest. Practice with it a bit and you'll see what I mean.
In answer to your question the height of your tree won't make a whit's difference in your 270's trajectory.

-As a side not I was setup in my treestand with loop rest, 300 WSM and TDS Reticle in a tree sighted over a field where up to a 400yd shot was possible. I figured I was ready for a long shot.........then the nice 8pointer walked UNDER my tree and I shot him 17yds away!..........................DJ

20 feet is about 6.67 yards. Take the arctangent of (6.67/300) and you'll get about 1.27 degrees. My old Lyman manual has a table in which it says a .308" 180 grain Sierra BT launched at 2600 fps will be off less than an inch at 300 yards when a 15 degree angle is involved. So an angle of less than 2 degrees would seem to have a negligible effect in your situation.

Mathman,

You're correct on the angle if he was shooting at a deer lying on the ground. I was assuming he was shooting at a standing deer that had lungs 36" off the ground. <img src="/ubbthreads/images/graemlins/wink.gif" alt="" />

Then it should be 17' shouldn't it? The deviation from horizontal comes from the fact he's 20' in the air.

Mathman,

That's right. Of course, if he's sitting on top of a 20 ft stand, instead of the gun being 20 ft off the ground when fired, then we would be back to your scenario of about 20 ft difference between the gun muzzle and the target. Glad you could add the number for an angle of 15 degrees to the thread -- I knew it would be negligible, but didn't have the number to back it up.

RR,

I was already typing my first post, in which I didn't worry about the height of the deer <img src="/ubbthreads/images/graemlins/grin.gif" alt="" />, before your first post appeared. Furthermore, I believe I misread your first post when I did see it. So we're not arguing about anything, it's a miscommunication on my part. Like you said, the trajectory difference in the questioner's scenario will get lost in the noise of the field shooting situation.

mathman

When shooting at acute angles no matter whether up or down the bullet strike will always be higher than when shot on a dead levle.

In the case you cite though it won't make a bit of difference practicly speaking.

Just aim where you want the bullet to go.


BCR

BTW welcome to the fire.

do like i do, shoot it. set a piece of plywood out at 300 yards and shoot it, from your elevated position. that's the only way you will really know for sure.

Yea just be sure and hide the rope that you use to tie the deer down in front of the plywood................... <img src="/ubbthreads/images/graemlins/smile.gif" alt="" /> <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />..............DJ

Boggy said what I was going to. If you don't trust Boggy, you could try trusting me. Or, if you don't trust me, try trusting Boggy.

I think you'll do okay either way on this one. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />

Thanks guys, you've all got different takes on how to figure this one out down to a fraction of a degree! Whether the deer's lungs are 3 feet off the ground and the height of my muzzle being also 3 feet above the tree stand base is true. I was hoping to tap into your knowledge and experience on this one! Now I know not to hold 12 inches high or 12 inches low. I have a solid rest on my stand that swivels and moves in and out quietly. So thank you for answering my question and I might ask another question that I have always wondered about another time. It is good to be around other experienced hunters. I live in southwestern Ontario and hunt deer, turkeys(shot my first this spring 21 pounds!),moose,ducks and geese. Talk to yas later.Chris.

As has probably already been said, the distance to the target should be measured from the bottom of the tree to get the proper distance.

The distance higher up say from a tree stand is the hypotenuse of a right triangle. That's the "true" distance, but gravity doesn't recognize angles and only acts on the horizonal distance.

As far as 20 feet high up, I don't think it would make much of a trajectory distance, but it might make a "sight picture" difference.

Not that it would matter from a tree stand but a bullets drop
depends on the time of flight not the horizontal distance traveled. The trignometric calculation is to calculate what part of the drop affects the point of aim (it ain't much). Shooting up or down hill is a favorite excuse of a Gun Writer when they miss.
Good Luck!

While what you say is true, it's also not quite the full story. A 270 is going to travel the same velocity whether it's in a tree stand or on the ground.

Actually, a bullet falls at the rate gravity affects it and the time of exposure to gravity. Since gravity only pulls straight down, it matter about the angle.

Shooting uphill or downhill, tendency is to shoot high because of this.

chevychris,
The angle from the tree will make no practical difference, but being zeroed only 1.5" high at 100 yards will. This will limit the point blank range, and require hold-over at 300 yards. Better to zero 2.5" high at 100 yards and extend the point blank range. Most people are poor at estimating range, so being able to hold in the chest to the maximum practical range gives a definite advantage. It would be a good idea to practice at the various ranges to be sure what the rifle is actually doing.

Chevy,
You have good information above, and my respect to those who recognize this as a trig issue, and not a physics one.
That said, be more concerned about your close-in shots. If you aim for the shoulder as you would on flat ground, you may "foreleg" an animal, or only get one lung, particularly if you have a scope with a huge objective lens requiring it to be mounted high above the bore..

Don't think so, Scott. Everything that moves is a physics issue.

A squared plus Bsquared = C squared. Instead of looking at the C, the hypotenuse, you should be looking a the B leg distance.

But from a tree stand, that's not to worry. When shooting uphill or downhill at an goodly angle, your aiming along the hypotenuse, and you'll shoot high every time, even if you use a rangefinder.

Not a physics issue.
Your physics variables remain the same:
Acceleration of gravity 32 fps/ps
Range = x
Time of flight = y
Bullet drop = z
What changes is your angle, and that changes your perspective of the target. It's very well explained in the Sierra handloading manual.