How much difference does gravity have on a bullet when shooting down hill

cavan shooter

Guys
We all know that a bullet will drop over a distance as it slows down and gravity takes over, but if you where shooting downhill how much of an additional difference would it make over a typical 100m shot, and is there a ready reckoner that is handy to use, I myself typically shoot the 22 lr and Hornet

deerhunter1

cavan shooter wrote: »

Guys
We all know that a bullet will drop over a distance as it slows down and gravity takes over, but if you where shooting downhill how much of an additional difference would it make over a typical 100m shot, and is there a ready reckoner that is handy to use, I myself typically shoot the 22 lr and Hornet

This might give you a bit of info

Angle Cosine Indicator Aids Hunters « AccurateShooter.com Bulletin

It wasn't me!

If you're shooting at an angle, you always, always aim low, regardless of whether the angle is up or downhill. This is because gravity is acting vertically; therefore, if you're shooting at a two hundred yard target downhill, the distance, were the target at the same level, would be less. Since gravity is only acting across this distance, the drop will be the same as if the target were closer. Now, most centrefire cartridges shoot flat enough that within two hundred yards, you can ignore all but quite a strong angle. However, shooting up or downhill, the correction for angle will always be to aim lower than you would if the target were on the same level and a correction were necessary.

johngalway

I've deleted a few replies, my own included as they don't help the OP above and beyond the replies which were left.

FISMA

Cavan_Shooter,
This one bothers me still. I have to sit down and really go through it.

The instant your bullet clears the barrel, it is, for most intensive purposes, free falling at g = 9.80m/s^2. The Gravitational Force pulls the bullet towards the center of the Earth, which is pretty much perpendicular to level ground, in general. The Gravitational Force accelerates the bullet's mass at local free fall g values. Not much variance, unless you are talking about the North Pole versus the equator.

If you were to drop a bullet, from the same height, the instant a horizontally fired bullet cleared the barrel, both rounds would hit the ground at the same time. There's probably factors that will slightly effect fall times, like: heat, humidity, thermals, and such. However, not by much.

g is 9.80 meters per second, per second. g tells the bullet that every second, it must speed up by 9.80m/s, until it hits terminal velocity.

ItWasn'tMe is correct, whether shooting uphill or down, always aim low. That's because your scope is calibrated for the horizontal. Thus, it's the horizontal distance between you and the target that matters, not the angled.

Since the angled distance is greater, you will tend to shoot high when referring to the horizontally set scope markings. That's why you shoot lower than what you would think.

Does that make sense?

Also, the 22lr will make a big difference due to its low speed and mass.

I was at the range the other day and I scoped the 22LR in at 50ya, spot on. At 100ya, I was 5inches low!!! Something I am definitely not used to, shooting the 30-06.

Again, as ItWasn'tMe has stated, the flight time of the big rounds is so small, the drop is not noticeable. Indeed, I myself offer more variance in the shot than the big rounds.

The Leica 1600 offers an internal ballistics calculator which will tell you what to look for in your scope. Some scopes, like Burris, will put a dot in your scope, telling you where to shoot.

I have a Leica 1200, (thanks Kay_9) and I do not plan on getting the 1600. Personally, I want to leave a bit of chance, intuition, or sportsmanship in the shot.

I call it hunting. I call it Fishing. I do not intend on calling either catching.

No disrespect for those that use the 1600 types. I may get one when I get good enough to reach out to 600ya, Right now, I stay within 400. Usually, 300 or less.

cavan shooter

Many thanks for what are good practical answers, the short of it you aim low.

How low depends, so best to practice:)

This is the kind of stuff that makes for good stickies, clear, concise no BS.

Vegeta

Off the top of my head.

To calculate the effective distance it is the straight line distance as found by a range finder multiplied by the cosine of the angle.

So for example, lets say the angle is 30 degrees. The cos of that is ~0.866. The straight line distance as found with a range finder is 400 yards.

(0.866)x(400) = 346.4 yards

So gravity only effects the bullet for ~346 yards

Now with a .308 and a 155 grain bullet in a ballistics calculator that is a difference of 8 inches if not factored into the shot.

I've seen scope attachments which give the cos of the angle. Kind of like a spirit level type thing for quick calculations

Tackleberrywho

So if you are at an angle, climb up higher, and then feck the cos Sin or Tan!!


What did we do with out all the modern toys

30 degrees is in real Terms the max one would be shooting.
Most shooting is not much more than 15 or 20 degrees of the angle horizontal with the ground

It wasn't me!

Tackleberrywho wrote: »

So if you are at an angle, climb up higher, and then feck the cos Sin or Tan!!


What did we do with out all the modern toys

30 degrees is in real Terms the max one would be shooting.
Most shooting is not much more than 15 or 20 degrees of the angle horizontal with the ground

No, you just learn how to do it and shoot, same as for wind or estimating drop beyond your given zero. It's all part of the hunting skillset. Also, shots can be steeper than 30 degrees, by a decent margin. Maybe not on lowland fallow, but there's plenty of hill stalking for sika in Wicklow that could involve steeper shots.

rrpc

That diagram doesn't illustrate the principle anyway. What you need to visualize is a right angled triangle with the hypotenuse (the long side) being the line to the target and the adjacent side being the actual straight line along which gravity gets to exert its pull.

Here's a more apropriate one:



c is the line to the target and b is the line that gravity works on. If you visualise c as being level, your sights have been set to compensate for the bullet drop over that distance and so when you shoot up a hill, the bullet drop won't be as much and you therefore have to aim lower. The same will apply when you shoot downhill as it's just a case of mirroring the triangle on the b side.

cavan shooter

Many thanks for the answers,

Vegeta

It wasn't me! wrote: »

No, you just learn how to do it and shoot, same as for wind or estimating drop beyond your given zero. It's all part of the hunting skillset. Also, shots can be steeper than 30 degrees, by a decent margin. Maybe not on lowland fallow, but there's plenty of hill stalking for sika in Wicklow that could involve steeper shots.

Yup that's what I was thinking about when I posted. Or one particular permission for rabbits which is a big valley and both sides are steep.

Also the Ballistic FTE App on the iphone has a function which will account for this. Turn it on and when you tilt the iphone it adjusts the MOA corrections in real time. Thought it was pretty cool

Solidchrome

Does any of this apply to 12g?

hatebaggers

ive lurked here a while, only bothering to post because this thread has has gotton under my skin, there are a few replys here which in no way helped the op, stupid comments also like''30 degreesis in real terms the max one would be shooting'' thats a stupid assumption to make , it may be your max angle in your local terrain but not everyone elses. the same poster put up a pointless diagram which in no way helped or described what he was on about, more evidence that he has no experience or little knowledge of the subject and therefore is not helping the op in anyway. end of rant anyway here is something iv posted before elsewhere

people can get way too hung up on this subject , a little knowledge can be a dangerous thing! firstly yes if you are shooting up or downhill and you dont compensate for the angle your round will impact high..fact.
also it is more accurate to multiply your dope or elevation clicks by the cosine angle than it is to multiply the range to the target by the cosine angle. this is called the improved riflemans rule.

however what happens in real life in the field is this(from what ive seen) 1) people have read this somewhere and so say i must aim low , sometimes too much and miss ..why ? because they dont know how much to compensate and just guess.2) people dont compensate at all and miss and blame the angle(sometimes it can be because they didnt compensate and sometimes its because they just pulled the shot or rushed it and miss simply due to a poor shot. thats right they missed not due to the fact they didnt compensate for the angle but due to a poor shot, then they blame it on forgetting to compensate for the angle or not compensating enough. il explain further.
my dope for 168gr 308 at 350m from a 100m zero is 2.2mils or 22 clicks up , for 400m it is 2.8mils or 28 clicks up. now lets say im shooting at 30 degrees of angle and i laser my target at 400 what should i dial on my scope to hit ? simple .. im taking the cosine of the angle 30 degrees (.87 ) and multiplying it by my 400m dope..so 28*.87= 24.36 so i now dial 2.4 mils or 24 clicks up on my scope
so we now see a differnce in what i dial on my scope of .4 mils or 4 clicks each click is worth 1cm at 100m so 4 clicks at 400m is 16 cm. if i had not compensated i would have struck high by 16cm
now my real point is what differnce would 16 cm really make.. nothing really on a deer , not even on a fox sitting straight looking at you .
the reason i picked 400m and 30 degrees for this example is just to show an average shot, lots of people would have over compensated this shot if they were just guessing what to hold. you really need to be able to know when stuff will ACTUALLY matter to your shot or not . obviously it becomes more important with steeper slopes and bigger distances.
and just to show what the differnce is between multipling the cosine by the range vs by your dope .. 400*.87=348 so i would have used my clicks for 350 which is 2.2mils or 22 clicks as opposed to the24 i got using the improved riflemans rule and so a difference of 8cm .
an aci mounted on your rifle can be handy for calculating what you need to dial , but you need to ask yourself am i shooting at distances and steep enough angles and at small enough targets to need to worry about this. ( just my 2 cents . your milage may vary . oh and i dont think you should be worring about it with a 12g !!
my 308 wiyh aci mounted

Tackleberrywho

cavan shooter wrote: »

Guys
We all know that a bullet will drop over a distance as it slows down and gravity takes over, but if you where shooting downhill how much of an additional difference would it make over a typical 100m shot, and is there a ready reckoner that is handy to use, I myself typically shoot the 22 lr and Hornet

A good range finder combined with a cosine indicator may be of some help.
however for a .22lr or a hornet on foxes or bunnies shot placement at any distance over 100 is more important to ensure kills.

Most fellas who shoot out past 400 may use a lot of equipment.
However a bunny @100 with your .22 or a fox @150 with the Hornet they will be just more equipment to fiddle with.

As most fox shooting is done @ night the range is reduced to the effective range of the lamp (lightforce 170 being an exception)

Anyone who does a lot of lamping shoots sub 200 yards mostly with centrefire as the angle compensation is not a major issue

hatebaggers

''a good range finder combined with a cosine indicator may be of some help'' of course its of help its what its designed for , thats like saying a car may be of help for driving !
as for having these two items and it being just more equipment to fiddle with if shooting buunys at100 and foxs at 150 i think my post clearly illustrated if you read it that you need to be shooting large ranges and steep angles to have this come into play, and then if you do have a shot that requires it then it takes all of a couple of seconds to lase your target and a second to look at your aci. as my post showed albeit with a 308 not a hornet ( however the 308 drop over distance is considerable ) that even at 400 and at 30 degree it wasnt really worth worrying about with. thats why i have an aci on my 308 and not on my 220 swift. have you worked out what a 22 hornet is dropping every 25m between 100 and 150m? now compare that with what you would have to compensate for with a 150 m shot at 30 degree say and you will realise you should probably be more worried about judging your distance to the target accuratly than a small compensation for angle. now if it is at a big enough range and angle then i think its worth the extra moment or 2 to ''fiddle'' with the equipment so you dont just fire off any old shot and end up with a wounded animal.

cavan shooter

Tackleberrywho wrote: »

A good range finder combined with a cosine indicator may be of some help.
however for a .22lr or a hornet on foxes or bunnies shot placement at any distance over 100 is more important to ensure kills.

Most fellas who shoot out past 400 may use a lot of equipment.
However a bunny @100 with your .22 or a fox @150 with the Hornet they will be just more equipment to fiddle with.

As most fox shooting is done @ night the range is reduced to the effective range of the lamp (lightforce 170 being an exception)

Anyone who does a lot of lamping shoots sub 200 yards mostly with centrefire as the angle compensation is not a major issue

Tackleberry and hatebaggers, I think you've summed it up quite nicely, over the distances I would be shooting its not something to be worried about.

To be honest I dont go for 10 cent size targets over massive I aim for a 3-4 inch target (if you get my meaning) 2 inches high to 2 inches low i.e I go for MPBR.

Taking all that into account and now knowing (thanks to you guys) I'm to aim lower is what is important. How low could be negligible, depending on the angle.

Solidchrome

OK- you guys have made my head explode

Think I'll just carry on with aim and shoot technique...

pedroeibar1

hatebaggers wrote: »

...... there are a few replys here which in no way helped the op, stupid comments also like''30 degreesis in real terms the max one would be shooting'' thats a stupid assumption to make

....... <snip> (load of waffle.....)
another <snip> of more waffle such as .. 'just to show what the differnce is between multipling the cosine by the range vs by your dope .. 400*.87=348 so i would have used my clicks for 350 which is 2.2mils or 22 clicks as opposed to the24 i got using the improved riflemans rule and so a difference of 8cm . <snip>

Akshully, the OP asked 'shooting downhill how much of an additional difference would it make over a typical 100m shot, and is there a ready reckoner that is handy to use, I myself typically shoot the 22 lr and Hornet'

Whatever happened to fieldcraft? I cannot figure out which is worse, shooting rabbits downhill at >100m with a 22lr or pompous OT posts about math that few understand and even fewer care about. Some guys on here need to get a life:rolleyes:
P.

It wasn't me!

pedroeibar1 wrote: »

Akshully, the OP asked 'shooting downhill how much of an additional difference would it make over a typical 100m shot, and is there a ready reckoner that is handy to use, I myself typically shoot the 22 lr and Hornet'

Whatever happened to fieldcraft? I cannot figure out which is worse, shooting rabbits downhill at >100m with a 22lr or pompous OT posts about math that few understand and even fewer care about. Some guys on here need to get a life:rolleyes:
P.

To be fair, it's a useful piece of knowledge. Nothing wrong with having it, discussing it and passing it on, no need to "get a life" as a result of that. It might even save you a wounded animal at some point or an unnecessarily long follow up. It might even make the difference between a successful hunt you've spent a lot of time and money preparing for and a very expensive failure. What happened to fieldcraft? In respect of shooting, this *is* fieldcraft! You're really flying off the handle here, completely unnecessarily. To take a practical example, you're shooting at a rabbit at 100 yards, downhill, at such an angle that the real distance in terms of trajectory is 75 yards; without knowing how to alter your hold off point, you'll at best miss the bunny, or at worst put a round through its ears, wounding it by holding over as if the shot were at 100 yards on the level. Now, knowing that is the difference between a clean kill and a wounded animal. That's important.

pedroeibar1

It wasn't me! wrote: »

To be fair, it's a useful piece of knowledge. Nothing wrong with having it, discussing it and passing it on, no need to "get a life" as a result of that. It might even save you a wounded animal at some point or an unnecessarily long follow up. It might even make the difference between a successful hunt you've spent a lot of time and money preparing for and a very expensive failure. What happened to fieldcraft? In respect of shooting, this *is* fieldcraft! You're really flying off the handle here, completely unnecessarily. To take a practical example, you're shooting at a rabbit at 100 yards, downhill, at such an angle that the real distance in terms of trajectory is 75 yards; without knowing how to alter your hold off point, you'll at best miss the bunny, or at worst put a round through its ears, wounding it by holding over as if the shot were at 100 yards on the level. Now, knowing that is the difference between a clean kill and a wounded animal. That's important.

Most knowledge is useful, but not all is relevant or necessary. In the situation you describe – shooting at a rabbit at 100 yards, downhill, at such an angle that the real distance in terms of trajectory is 75 yards - you would be situated about 65 yards above the target. In effect, you would be shooting a rabbit in a deep hole. Now how often does that happen? Bullet drop for a 22lr at 100yds is say 3 inches and at 75yds just a bit less. If you don’t know, trying to calculate it by working out sines and cosines on the side of a cliff with bunny in your sights down below is not a possibility. So, fieldcraft would dictate that you get closer for a safer/more humane shot. (Or not climb the cliff in the first place!)

The type of info (the good stuff, that is) being bandied about here is – to be charitable - an academic exercise and fine for long range shooters of calibres greater than .22lr and better done under range conditions.

FWIW I would have answered the same way had someone started to post similar about shooting pheasant at >65 yards with a 12g.

P.

cavan shooter

pedroeibar1 wrote: »

Akshully, the OP asked 'shooting downhill how much of an additional difference would it make over a typical 100m shot, and is there a ready reckoner that is handy to use, I myself typically shoot the 22 lr and Hornet'

Whatever happened to fieldcraft? I cannot figure out which is worse, shooting rabbits downhill at >100m with a 22lr or pompous OT posts about math that few understand and even fewer care about. Some guys on here need to get a life:rolleyes:
P.

Is there something wrong with shooting rabbits down a hill at 100 meters, I have been doing so at 50-100 meters since I first got a rifle licence at 18 and never had any hassel.

Is it not within the capabilities of a properly zeroed 22lr, ammo, scope and shooter. Properly set up, the rifle and you have a 3 inch kill zone on a rabbit, and with a mil dot zeroed as mine for 70 m, the first dot down 100m.

Now the 30 degree angle lads are chatting about wouldnt be a typical scenario around me but, Thats how the lads explained it and looking at them and there calibers they like long shots, I assumed they punch paper at that distance not game.

(if you really want to get excited about it you can) and at distance there is a difference and you can get gadgets. :cool:

But over the ranges I mention there is a bit of a hold under, if you want to know what go practice on some plates.

Is it not about understanding what you should do to ensure a good shot.

pedroeibar1

OP

cavan shooter wrote:

Guys
We all know that a bullet will drop over a distance as it slows down and gravity takes over, but if you where shooting downhill how much of an additional difference would it make over a typical 100m shot, and is there a ready reckoner that is handy to use, I myself typically shoot the 22 lr and Hornet .

And now we have reached

cavan shooter wrote: »

Is there something wrong with shooting rabbits down a hill at 100 meters, I have been doing so at 50-100 meters since I first got a rifle licence at 18 and never had any hassel.

(snip)

TBH, Cavan, with the content of your last post you're proving my point. In fact, why did you bother with your opening post if you are such an expert?:P:)

The scenarios that 'some people' started to pontificate about had nothing to do with a .22lr and clearly are more for the paper guys - and good luck to them, let them have their fun.

I believe in clean kills and safe shooting. 99.9% of the hunters I know would not be too fond of cosines, inclinometers and anemometers.
And the few ghillies I have met would tell a shooter where to put them:D
Rs
P.

rrpc

pedroeibar1 wrote: »

The scenarios that 'some people' started to pontificate about had nothing to do with a .22lr and clearly are more for the paper guys - and good luck to them, let them have their fun.

The 'paper' guys don't need this info as we never shoot downhill or uphill other than at tiny margins. Most ranges are relatively flat.

Vegeta

cavan shooter wrote: »

Is it not about understanding what you should do to ensure a good shot.

Bingo

It is my opinion that if someone asks a question, you explain the basic principles so they can understand it better.

There's no point in just telling someone to aim low. The immediate next question is "How low?"

You tell them the basics, how to work it out for themselves and then go to the field and practice until you are competent.

Apologies for using the .308 as my example Cavan Shooter but it is difficult to get a ballistic calculator for a .22lr at the best of times, let alone in work where most shooting sites are blocked.

It's similar to give a man a fish and he wont be hungry that day, teach a man to fish and he wont go hungry again.

cavan shooter

pedroeibar1 wrote: »

OP


And now we have reached


TBH, Cavan, with the content of your last post you're proving my point. In fact, why did you bother with your opening post if you are such an expert?:P:)

The scenarios that 'some people' started to pontificate about had nothing to do with a .22lr and clearly are more for the paper guys - and good luck to them, let them have their fun.

I believe in clean kills and safe shooting. 99.9% of the hunters I know would not be too fond of cosines, inclinometers and anemometers.
And the few ghillies I have met would tell a shooter where to put them:D
Rs
P.

Because I wanted to know....thats why....
why does someone ask other questions on here, in fairness It was answered with good explanations as I have sumarised.

Living in cavan as I do there is slopes hills and valleys, and normally I would be shooting at shallow enough angles up to a drop in 20-30 feet over that 100 meters or so.
So I thought it a fair question, Does it have an effect
I didnt realise it would upset people:(

As for the gadgets, everyone to there own, I am sure a telescopic sight was frowned upon as a gadget and at one time seen as un sporting, so I have no opinion either way

CJhaughey

Actually this is a good topic, outside of Ireland shooting at angles of 30º and more can be common.
Ever seen the kind of country Thar and Chamois inhabit?
You would want to know your stuff if you wanted to shoot those animals.
Even in Ireland I can think of several places where a shot may have to be taken in a less than flat area for deer and goats.

pedroeibar1

cavan shooter wrote: »

Because I wanted to know....thats why....
why does someone ask other questions on here, in fairness It was answered with good explanations as I have sumarised.

Living in cavan as I do there is slopes hills and valleys, and normally I would be shooting at shallow enough angles up to a drop in 20-30 feet over that 100 meters or so.
So I thought it a fair question, Does it have an effect
I didnt realise it would upset people:(

As for the gadgets, everyone to there own, I am sure a telescopic sight was frowned upon as a gadget and at one time seen as un sporting, so I have no opinion either way

Not upset, just was doing a bit of pi$$taking on what I saw as total overkill in responses to a simple question about shooting a 100yd bunny.;) (My Mod-deleted post would have shown that.)

Apologies to TNT and ‘Downhill Racer’

http://www.youtube.com/watch?v=Ur-pdd8EnOo

New words :


The range is straight and narrow
His heart's in overdrive as he aims away
High away from the ground
His eyes are black and empty, and the nights are all the same
Has he lost control, sells his soul
For a ticket to the rifle range
Caught inside the devil's open door
Highway to the morning sun he rides
Ballistics control his every stride
Highway to the morning sun he rides
All the way to the gates of hell he flies
Another downhill shooter



I'll shut up now.:P
P.

Tackleberrywho

457 yard bunny yesterday evening @ dusk


I'll let yee lads fight over the angle!

I used Bullet drop and range to estimate "in my head" where to aim.
I was off by 2" but i still popped Bug's

rrpc

Backstop?

johngalway

Last chance guys.

OP asked a question, if you have no decent contributions to make to the topic of the thread then don't.