Shooting on angled slopes
To all those snipers out there:
I just want to clarify the correct order on accounting for bullet drop if you are aiming uphill and aiming downhill.
If you are aiming uphill, would you want to aim lower on the animal?
If you are aiming downhill, would you want to aim higher?
The basic rule of thumb is that you would shoot for the horizontal distance. Which is shorter than the slope distance you are seeing the target at. So, for an uphill target you would aim a little lower, and the same for the downhill. It's really more complicated than this, but for a general rule of thumb the horizontal distance works.
The problem is that most people subconsciously aim TOO low and miss, just like many people aim TOO high when shooting at great distances when they try to compensate for the distance.
I say hold dead on where you want to hit. If your rifle is set for a 250 yard zero and the shot is 200 yards, the difference is not enough to bother with, nor is it with a 300yd shot. Hold behind the front leg for a double lung hit and pull the trigger. Don't overthink it.
If you are going to be shooting beyond 300 yards you really then need to start learning about ballistic tables and shooting your rifle a bunch.
short answer: same correction, how much of a correction now that depends on the distance, vel, angle, and point blank range of cartridge along with zero. Suffice it to say for flat shooting projectile (3000 fps or greater), zeroed for 250-300 yds., at an angle of 30 degrees or less you can prob get away with holding dead on, otherwise if you don't want to do the cosign angle bullet drop correction prob shouldn't shoot.
The easiest way to put it -
Angle (up or down). Your shot just got easier (closer).
Steep angle. Your shot just got alot closer.
All those guys are right. Resist the urge to aim high if you range the animal on a steep slope and it line of sight a long ways away. All the goat hunters I was with last fall who missed on steep angles shot over the goat.
Don't hold high or low. Learn your rifle, learn your scope, range it, dial it, hold dead-on. One shot, one kill.
Originally Posted by Mountain Man Jack
I used to have a tall touret scope that I could "dial" in. It didn't survive my hunts too well and after being repaired it now graces my varmint rifle.
Yes, aim lower when shooting both up or down
... but not too much so, as already said. It's usually right to aim 1, 2, or 3 inches (larger with more elevation difference, and your cartridge greatly varies) low and no more.
The basic reasoning behind this is is clearer if you first take it to extremes - if you shoot straight up or straight down you'll have zero "bullet drop", i.e., the bullet will go perfectly straight - no arc. And the closer you get to perfectly horizontal, the more bullet drop you have, i.e., the more arc your bullet will take.
Muzzleloader hunters can make the largest adjustments, I think because bullet weights are usually heavier, but someone chime in if its something else.
It's not bullet weight. It's velocity. Gravity accelerates all projectiles toward the earth at the same rate regardless of their mass: 9.8m/s^2 (32ft/s^2).
Originally Posted by FamilyMan
Slower-moving projectiles are acted on longer by gravity before they can travel the same distance, and so move more toward the center of the earth over that given distance. At 100-150 yards (the usual limit to which many muzzleloader hunters restrict their shots) it shouldn't be much.
The answers here are basically correct. Another thing to consider, which was brought up in a similar thread a while back, is the path of the bullet through the animals body. If you are shooting a steep downhill you will want your bullet to hit higher on the body and shooting steep uphill you want the bullet to hit lower on the body.
Heres a tip of what I do, for those of you that use range finders. If the shot is in fact a long one uphill or downhill quickly draw an imaginary line from where the animal is either uphill or downhill to what would be level with you. Range that and you'll have your distance on a level plane of how far the animal is from you, and shoot accordingly. This works well when an animal is at a distance away from you on a slope but not directly beneath you (you cant range air..grin). I have shot two animals at extreme angles (sheep and a moose), both straight downhill and have found that if the animal is no more than say 150 yards either up or down with most hunting calibers, just hold dead on. If you ranging the critter at 300+ figure out how far he is by using the imaginary line technique. Good range finders are your best friend! In most cases holding dead on works fine (give or take a 2 MOA difference), but if the range is really extended thats when things get tricky, Have had buddies tell me stories of sheep they have missed in the 300-400 yard range because of angles reaking havoc on their shooting abilities even though a 300 or 400 yard shot is something they are proficient at.
Velocity nor weight of the projectile make a difference with respect to gravity.
Drop a 180 grain bullet from shoulder height and it will fall onto the earth at exactly the same time as a bullet fired from a level rifle, on level ground, from shoulder height.
Welcome an uphill or downhill shot as an easier shot and call it that. How much easier? Now that requires a formula...
To answer the inital question: all good answers here, although I agree with always holding on fur unless VERY long range. Plenty of time to scratch your head on hold over and windage at those distances. Also time to sneak a lot closer and make it easier.
Now, having passed on a VERY, VERY long shot straight down once upon a time I wonder if any one will chime in on this one. Despite what is commonly depicted in charts a bullet never climbs above the level of the bore at any time in its flight. It doesn't produce lift so it cann't go up. To overcome this we angle the level of the bore upwards with respect to the sights so the round climbs above the line of sight then gravity will drag it downward untill it recrosses the line of sight at the sight in range.
If you are shooting straight down all gravity will do is accelerate the bullet. It should also continue to deviate from the line of sight at the intial angle rate getting farther away as it goes. No gravity to pull it back down. Thus making a say 600 yrd straight down shot pretty hard to predict.
What have I missed in this?
Gravity will not accelerate the bullet as it is allready well past terminal velocity at the muzzle. The bullet will continue at whatever slight upward angle you sighted into the rifle as you mentioned above untill it strikes the ground. I would hold at the bottom 1/3 of the kill zone and gently squeeze the trigger...
Exactly so. I meant only that a bullet leaving the muzzle at 3000 fps will cover 100 horizontal yards faster than a bullet leaving the muzzle at 1100 fps. And thus it will reach a 100 (horizontal) yard target having dropped less distance than the slower bullet.
Originally Posted by Marc Taylor
True. But it's also hard to imagine. Where would you stand/sit/lie for a 600 yd straight down shot? That'd be one heckuva cliff. I don't think I'd have the guts to lean out over the edge and shoot down it. Maybe if a buddy had a couple of ropes around my waist and armpits...
Originally Posted by Daveintheburbs
Either that, or you've taken the notion of a treestand waaay too far.
Bullet drop is based on gravity and the effect of gravity is based on time. Gravity *pulls* and object toward the earth, perpendicular to the plain of the Earth at an accelerated rate of 32'/sec/sec minus drag coefficient of the atmosphere. After 1 sec, an object falls about 16 ft, and after 2 seconds about 64'.
This is true no matter what the angle of the shot is. But....when shooting uphill or downhill your sight plain (straight line distance) is NOT perpendicular to the plain of the Earth (horizontal distance). The net effect on the bullet drop along its path would be the same as the horizontal distance. The difference between sight plain (scope) and bore plain complicate the calculations.
As Alaska Cub said, shots less than 200 -150 yds are going to be affected very little. 300 yd shots may provide a little challange at very steep angles. Over 300 hundred yards, you better be getting a range finder and ballisitcs calc.
Well past terminal velocity? Is that like going 150% of your car's maximum speed?
Originally Posted by LuJon
There are range finders that tell you the true distance with the angle adjustment. Rather than try to do a vector formula in the mountains, spend the extra $100 and shoot your animal...