Thread: Downhill shot

So I had a weird one just before christmas. Spiker 300 mtr very steep uphill, me on same face shooting up. Deer were onto me. Shot 2506 holding forward shoulder to allow for some drop. Hit the deer in the leg elbow, rolled down stood up hit in leg again ??? Had to find and finish.
On a level shot this is a no-miss rifle zeroed 2" high at 100 4-12 FFP scope cranked up ??? Ideas ??

Originally Posted by Moa Hunter

So I had a weird one just before christmas. Spiker 300 mtr very steep uphill, me on same face shooting up. Deer were onto me. Shot 2506 holding forward shoulder to allow for some drop. Hit the deer in the leg elbow, rolled down stood up hit in leg again ??? Had to find and finish.
On a level shot this is a no-miss rifle zeroed 2" high at 100 4-12 FFP scope cranked up ??? Ideas ??

shot a fallow thru above the knees years back man it made it easy to carry without that bone digging into your shoulders
it was like bag straps

Originally Posted by Moa Hunter

So I had a weird one just before christmas. Spiker 300 mtr very steep uphill, me on same face shooting up. Deer were onto me. Shot 2506 holding forward shoulder to allow for some drop. Hit the deer in the leg elbow, rolled down stood up hit in leg again ??? Had to find and finish.
On a level shot this is a no-miss rifle zeroed 2" high at 100 4-12 FFP scope cranked up ??? Ideas ??

the steep uphill bit threw out your usual good position/hold,tiny unseen tussock frond between you and animal,your normally spot on rangefinding was up shit creek and it was closer to 350,mars venus andyouranus were not pointing in same direction,it was a taller than normal deer,chamber was cold so pressure was low,your scales were acting up and was lighter load,powder was from slower batch,those dodgy trademe primers gave slower ignition, the dog farted...... take your pick,bottom line is you got the deer...I assume you rechecked zero afterwards???

Originally Posted by stug

There will be a slight difference between uphill and downhill. Uphill is going against gravity so will slow down a bit more, downhill is going with gravity so will slow down slightly less.

Actually wrong. Plug it into a calculator. At a given angle the corrections will be the same whether it's up or downhill. It's the angle from horizontal that's important, not the direction. That's why BDX style rangefinders also measure the angle.

Identify your target beyond all doubt because you never miss (right?) and I'll be missed.

Originally Posted by Eat Meater

Actually wrong. Plug it into a calculator. At a given angle the corrections will be the same whether it's up or downhill. It's the angle from horizontal that's important, not the direction. That's why BDX style rangefinders also measure the angle.

Identify your target beyond all doubt because you never miss (right?) and I'll be missed.

Calculators aside, how can that be, a bullet surely must have an advantage going downhill as opposed to up. A bullet not shot but dropped from the top of a cliff will accelerate to TV in free fall. A bullet is never going to fall upwards ( on earth) so the difference between the two is real

@tibo page 28 explains why there is a difference: Hornady 4dof technical document. I haven't confirmed if 4dof is more accurate. Also if you're using the Improved Rifleman's Rule (the cosine of the drop) a 100m zero is best.

Is this one for considering the Eotvos effect? On hares it may be but unlikely for our larger game, feral cattle etc.

I dropped the data into Trasol and Bullet flight and came up with much the same as above but with very small variances depending on azimuth and some extremes in temp. For hunting purpose I would recommend test firing at a variety of ranges and then using the confirmed data to build the drop tables for the game you are hunting. A hare at 500 meters requires more accuracy then a Wapiti at the same range as the critical area in each animal is of much different size. As long as you know this info you will be good. I cannot push taking time to get hard data by shooting the problem is the best way a sit is then a proven solution enhancing your confidence when the time comes. You will be able to relax and focus on making the shot. Have Fun.

Get closer.....???

My brain just about melted when read the first couple posts....

Sent from my SM-T225 using Tapatalk

Originally Posted by Moa Hunter

Calculators aside, how can that be, a bullet surely must have an advantage going downhill as opposed to up. A bullet not shot but dropped from the top of a cliff will accelerate to TV in free fall. A bullet is never going to fall upwards ( on earth) so the difference between the two is real

Yes but you have two different things. On an angle either up or down you still have a vertical distance for the bullet to drop. It's just way shorter sonic theoretically doesnt drop as far.
You also have a curved trajectory that allows for this and intercede at two points that allow us to work out an acceptable point blank aiming point.
When shooting vertically that first part takes over and it doesn't line up with the scope anymore at least at those two points.
A basic method is to aim low.

aim lower.....not so much low..do not aim off the meat,anytime at all, was bit of advice given to me years ago......

Originally Posted by csmiffy

Yes but you have two different things. On an angle either up or down you still have a vertical distance for the bullet to drop. It's just way shorter sonic theoretically doesnt drop as far.
You also have a curved trajectory that allows for this and intercede at two points that allow us to work out an acceptable point blank aiming point.
When shooting vertically that first part takes over and it doesn't line up with the scope anymore at least at those two points.
A basic method is to aim low.

But in my case shooting steeply uphill I hit low, and that with a TBR ??

Originally Posted by Moa Hunter

Calculators aside, how can that be, a bullet surely must have an advantage going downhill as opposed to up. A bullet not shot but dropped from the top of a cliff will accelerate to TV in free fall. A bullet is never going to fall upwards ( on earth) so the difference between the two is real

I struggled to wrap my head around it too because it does sound counter intuitive.

But the bullet is not being powered so the only forces are air resistance and gravity. Gravity will pull the bullet down at the same rate whether it's going uphill or downhill. Going up at say 100m/s means after 1s you're going up at 90m/s, and going down at -100m/s means after 1s you're going down at -110m/s. The difference in either case is -10m/s.

yes indeed but it will reach downhill target earlier LOL so your curved path comes into play..if its closer than your pointblank range on level ground it will be higher still as hasnt dropped back into line of sight....but I cant work it out in head so just get closer and shoot as normal LOL.

When I use Shooter and have a shot at 700 yds +35 degrees it says up 12.8moa, when I keep everything the same but switch to -35 degrees it says up 12.6moa.
So if the shot is long enough up vs down angle can be different.

Originally Posted by Moa Hunter

But in my case shooting steeply uphill I hit low, and that with a TBR ??

Maybe it was just a bad shot, bad load etc etc, it happens. Test rifle on range if all good don't loose any sleep over it.