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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 .
Sweet cheers will have a play on there calculatorQuote:
Originally Posted by 7mm tragic
Cheers- i know for next time!Quote:
Originally Posted by IamHackmeat
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?
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 curveQuote:
Originally Posted by Ross Nolan
Excellent reading material!! Thanks for the linkQuote:
Originally Posted by Magnetite
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!Quote:
Originally Posted by Jus
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
Quote:
Originally Posted by 7mm tragic
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.
Everyone has pretty much covered it - the steeper the angle, the less drop you have. If you were aiming for the chest then the shot going into the jaw isn’t a result of the angle though, that is just a result of how well you shot in that uphill position which can be tricky.
I would have to disagree, i had a great rest with bipod and no pressure as animal was standing front on and still , distance was fine,Quote:
Originally Posted by stagstalker
i aimed right in the brisket- shot felt good but went high- first time shooting at such a steep angle so hence why i asked question about change in point of impact and how to work it out should i be in that position again.
If it was on the flat i think there would have been no dramas- anyhow was a good learning experience for me
To be fair there is not many range finders now that don't have a tbr feature that allows for incline so will give you a corrected range to work with and a lot will give you a corrected adjustment in moa or mils if you have loaded your data.
Nice and quick out to 500ish
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270mtrs away...you aimed at brisket...... you should have hit the brisket...even on flat ground your bullet path SHOULDNT have climbed more than 3" high or dropped more than 3" low unless your using something like 44 magnum or 45/70 so the slope SHOULDNT have put you what??? 12-18" ----- 30-45cm high
because if the slope bit takes the range down........your bullet path is the same as at a shorter distance..so would be inside that 3"/75mmhigh or 3 low thing.
Accept it was just a bad shot. Suck it up and move on. We all make them from time to time. I just fucked up an easy shot at goat 45m 47 Attachment 243857degrees downhill. Time for smoko and admire the scenery. Attachment 243856
Did you clean your rifle barrel before this shot or was it a fouled bore?
Unfortunately projectiles can’t defy physics and climb - no matter how much angle there is. Assuming you have a 100, 200 or even 300m zero then it’s just not possible that the projectile climbed that much above your point of aim. If your expected point of impact at that range on the flat was say 5” low then a steep angle of say 35degrees might mean it only drops 3” (crude example).Quote:
Originally Posted by Hokistag
No shame in the shot, we have all had our fair share even when we felt it should have been good. A steep uphill shot is easy to get wrong, have seen mates who are good shots do it as have I.
By all means guys im not trying to defend the shot and it probably just was a shit shot on my behalf, rifle has been shooting great up until that shot - ive only asked the question because it had me puzzled why it shot so high and remember a mate having a similar circumstance shooting on a decline one time so wanted others opinion on how to tackle the situation next time which i have had a range of conflicting answers now.
Some say aim low others say it doesn’t matter- thanks for all the feedback its great to have these discussions and ive taken away some valuable info- best way to prove any of it is to go setup some targets and replicate the scenario then i can see for myself what theory is true😁🤙🏽
The effect isn't theoretical - it can be very easily and accurately calculated with the right inputs.
I looked at a few articles/vids on this topic, and this is the one that made most sense to me in explaining the science/maths behind it:
https://m.youtube.com/watch?v=wTSBcNgGMNo
Reading everyones answers I don't believe they are conflicting. Everyone is onboard with same principles of how the projectile reacts in relation to gravity and horizontal distance travelled.
There are two basic methods for managing projectile drop in the context of up/downhill shooting.
1. Hold over
2. Dial the scope
1. When the term "aim low" is used for holdover you need to understand the context. It doesn't mean aim lower than where you want to hit the animal, it means aim lower then you normally would for the same shot at a 0 degree angle as the bullet will still drop but it will drop less. In a nutshell, if you aimed 20cm high on a flat shot at 300m, then on a 30 degree angle shot at 300m you might only need to aim 10cm high and in theory are "aiming low" for that shot (just a crude example). If the distance is not far enough, then you need not worry, just aim and shoot.
2. Ballistic apps can have angle input manually along with the distance or most range finders these days give you true ballistic range (TBR) which rules out the need for a manual angle input. This is just a mathematical calculation that takes the angle of the shot into account with the distance and gives you a range that you can dial for. For example a 600m shot on a 30 degree angle might give you a TBR of 520m (just an example not legit numbers) so you then dial the shot for 520m which takes into account the fact that the projectile will drop less over the 600m shot because of the 30 degree angle involved.
With regards to missing high, that is common with a steep uphill shot. The way you align with the rifle in this scenario makes it very easy to exert forces upon the rifle with the shot that sends the projectile high. Downwards cheek pressure from trying to get under the scope and the rifle not naturally aligning in the shoulder etc as examples. My mate had exactly this happen on our Tahr trip last year on a steep uphill shot and missed him high over his back twice - its easy to do.
I agree mate. I’ve also found that shooting at the range in a controlled environment is easy to do. By comparison, shooting in the field even on flat ground with a bipod, one foot on hard ground, the other on soft (bouncy) ground, perhaps moss or tussock with a heavier recoiling rifle, the shot can be thrown off
Don’t know if your question is for me or original OP but the miss was eighth shot for the morning. Fucked up my running total for the month of 63 shots for 63 animals. Just a bad shot. Grazed r.h. side instead of centred shoulder spine shot from behind. At 45m dirty/fouled barrel makes fuck all difference, 1 Moa left at 200 yards with this rifle. Took second shot to get that goat, next eleven were clean shots so I stuffed up on missed shot. As I said before. Own your shots, suck it up if you miss and move on.
pythagoras theorem does have its uses.Quote:
Originally Posted by Ross Nolan
At normal distances, the bullet will strike just above the crosshairs. No need to make it more complex than that.
I also made a film about it
https://youtu.be/961eyQqusQ0
And just to mess with you... some lasers use cosine on range and not trajectory when calculating the "shoot to distance". That will place the shot low. And they do not tell you the math, so you have to test...
