Thread: Incline / decline shooting

Probably been asked before but i cant find the forum so here it goes again-
Had a situation the other evening spiker standing way up high on a slip about 30 degree angle from where i was laying down and at 270m , was standing front on had a good rest and took aim at chest but shot went high hitting jaw- second shot put him down but what’s everyones target when either shooting up or down hill? Cheers

Any slope either up or down will require less hold over. 45 degrees in theory will halve your drop. shooting straight up (not recommended) or straight down, no drop at all.
Remember bullet drop is due to gravity and exerts it's maximum effect when shooting perfectly level.
Have a play with Hornady's ballistic calculator on their website. You could enter the details of your above example to see if that accounted for your POI change.

aim lower than where you would on the flat do the same for down hill .

Originally Posted by 7mm tragic

Any slope either up or down will require less hold over. 45 degrees in theory will halve your drop. shooting straight up (not recommended) or straight down, no drop at all.
Remember bullet drop is due to gravity and exerts it's maximum effect when shooting perfectly level.
Have a play with Hornady's ballistic calculator on their website. You could enter the details of your above example to see if that accounted for your POI change.

Sweet cheers will have a play on there calculator

Originally Posted by IamHackmeat

aim lower than where you would on the flat do the same for down hill .

Cheers- i know for next time!

As an easy to understand rule, what effects the elevation is the horizontal length the projectile travels, as this is the part theat gravity, working perpendicular to the earths surface has to work on.
With this in mind, think of a right angle triangle with a long side of 270m, and an angle of slope of 30 degrees. The target will be 135m higher(or lower) than you, and the horizontal distance will be about 234m. If your rifle was zeroed for 234m it would be pretty much exactly on target shooting at that 270m 30 degree deer. The other thing to remember is that the wind has 270m of effect, so do your wind calcs on the actual distance the bullet travels, not the horizontal distance.

As others have said, it doesn't matter if you are shooting uphill or down - the effective distance for drop will be the horizontal distance, not the slope distance.

This is worth a read:
Sierra Inclined-fire

Basically, gravity works at a 90 degree angle to the earth, so the bullet is technically going a shorter distance through the effects of gravity at anything above or below shooting perfectly level, therefore less bullet drop when shooting at angles. I have found though, that when prone behind the rifle on a downhill slope, my body weight leaning into the rifle exerts different forces onto the stock than shooting uphill and having the rifle leaning back into me. Consistency is accuracy so potentially your shooting position sent the first high if it was floating against your shoulder a bit?

Originally Posted by Ross Nolan

As an easy to understand rule, what effects the elevation is the horizontal length the projectile travels, as this is the part theat gravity, working perpendicular to the earths surface has to work on.
With this in mind, think of a right angle triangle with a long side of 270m, and an angle of slope of 30 degrees. The target will be 135m higher(or lower) than you, and the horizontal distance will be about 234m. If your rifle was zeroed for 234m it would be pretty much exactly on target shooting at that 270m 30 degree deer. The other thing to remember is that the wind has 270m of effect, so do your wind calcs on the actual distance the bullet travels, not the horizontal distance.

As others have said, it doesn't matter if you are shooting uphill or down - the effective distance for drop will be the horizontal distance, not the slope distance.

Yer it makes sense now- not a position i have been in before so wasnt schooled on how to deal with it but simple science i guess and good learning curve

Originally Posted by Magnetite

This is worth a read:
Sierra Inclined-fire

Excellent reading material!! Thanks for the link

Originally Posted by Jus

Basically, gravity works at a 90 degree angle to the earth, so the bullet is technically going a shorter distance through the effects of gravity at anything above or below shooting perfectly level, therefore less bullet drop when shooting at angles. I have found though, that when prone behind the rifle on a downhill slope, my body weight leaning into the rifle exerts different forces onto the stock than shooting uphill and having the rifle leaning back into me. Consistency is accuracy so potentially your shooting position sent the first high if it was floating against your shoulder a bit?

Fair point- i do believe that could have contributed and the fact i put cross hairs too high and not compensating for shooting at angles which i now know about lol, glad i could pull off a follow up shot and put him down and also glad it wasnt a once and a lifetime animal!

Some of the newer rangefinders will take the angle to target into consideration and give you an adjusted range reading. Saves having to work it out yourself.

Sent from my SM-G525F using Tapatalk

Ive got an angle meter and trig app on my phone

Originally Posted by 7mm tragic

Any slope either up or down will require less hold over. 45 degrees in theory will halve your drop. shooting straight up (not recommended) or straight down, no drop at all.
Remember bullet drop is due to gravity and exerts it's maximum effect when shooting perfectly level.
Have a play with Hornady's ballistic calculator on their website. You could enter the details of your above example to see if that accounted for your POI change.

Cosine 45 = 0.707 near enough, not 0.5.

I wouldn't overthink it for closer ranges -

275m with my data is 1.3MIL for flat and 1.0 for -30 degrees. That is 34 vs 26cm.

Most people are very poor at judging slope - if you are not measuring it, it is probably less than you think. A scree slope is probably around 30-35 degrees as a useful reference.


If you don't have the equipment to measure, it's easy to over-correct for angle - at closer ranges (i.e. sub 400m) and not extreme angles (i.e. sub 30 degrees) you are probably best to aim "a fist or 2" low or just "take a couple clicks off" and call it good.


Poor shooting position on steep angles is probably responsible for more issues than actual ballistic effects - especially with heavier recoiling cartridges.