Shooting up hill/ Shooting down hill?

[Buffalobob]

BOB, dont feel bad about the misspelled name. it could have been worse.

The knowledge base of shooting uphill and downhill has constantly improved in the nearly decade this forum has existed. I merely hate to see an internet wonder dispensing advice that we have discredited long ago.

And where we are at the moment is exactly as you said

my engineer grandson simply holds his ipod next to the barrel and has an answer in seconds. usually while im looking for my chart.

No one who regularly kills animals at 1K and beyond will accept anything that looks like a one MOA error yet the internet wonder concludes.

most simplify it to cosine x distance others use thier drop tables for the distance to target and use cosine x drop the result is fairly close to each other less than 1 minute of angle.

That is an unacceptable error bracket for any single component of long range shooting when there are so many other sources of error that have to be accounted for.

 

[load]

Load thanks for the cannonball example, I found some similar analogies to satellite flight/launch and a golf ball example. I think I am on the same page and looking at the Sierra link (below) we can still pretty much assume gravity is a negligible based on it being constant (9.8m/s). I think I was confused more by semantics... time of flight vs gravity. As you mentioned there is some difference in the theoretical realm especially at extreme angles of 90 deg & 180 deg but am I correct that for trajectory calculations most will use it is not really a factor?

Sorry to beat a dead horse on this still trying to make sure I have a proper grasp on this topic. I am rally looking at this trying to determine at what ranges a rifle mounted angle indicator starts to reach its limit on usefulness and if there are any possible errors/assumptions to be aware of in most of the ballistics programs out there.

It has been over 20 years since I had to actually do the math and the trig and calc equation make my head hurt.


exterior ballistics

when you do the math on the figure showen on 5.2-1 it shows less drop than either the dropXcosine and distanceXcosine

from sierra

[FONT=arial,helvetica,verdana,sns-serif]Increase in [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]Elevation Angle Bullet Path Height [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]+/- 5 degrees .004 d inches [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]+/- 10 .015 d [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]+/- 15 .034 d [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]+/- 20 .060 d [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]+/- 25 .094 d [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]+/- 30 .134 d [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]+/- 35 .181 d [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]+/- 40 .234 d [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]+/- 45 .293 d [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]+/- 50 .357 d [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]+/- 55 .426 d [/FONT]
[FONT=arial,helvetica,verdana,sns-serif]+/- 60 .500 d [/FONT]​

which is (drop in inches x d)=X (drop in inches-X=adjusted drop)

three differnet equations three seperate sets of #s (this one is about 1/2 minute less than drop x cosine) blob would call this one unacceptble also.
bottom line just get out and shoot. without verifying all the math in the world will still end up in a miss

i use the ipod/bullet flight fte method myself it works however yet again isn't perfect.

 

[Buffalobob]

Now that you have finally figured it out, do the rest of the forum members a favor and don't give poor quality advice any more.

 

[rcdinaz]

okay, use the math; verify with practice and records; adjust to real world results... got it!

I will keep studying, I am also using Shooter for Android which seems to work well and is a bargain at $10.

 

[MontanaRifleman]

If a hunter was in a position to make a clean shot at a big fat White tail Deer that is standing broad side, and is up hill or in the same position but down hill, how should that hunter aim?
The hunter also knows the distance..

In my whitetail hunitng experience you will not find them very often in places where angle shooting is a factor. Now that we have that out of the way if you're talking mountain mulies, elk, sheep, goats, etc., just use a good balistics program that takes ALL the factor's into consideration including scope height.

Another thing you want to consider, is the bullets path through the animal at extreme angles. i.e., if you're shooting downhill, and you aim (corrected for angle) for the animals actual mid body (vs apparent mid body), your bullet will travel through the lower part of the animal and may result in a single lung vs double lung. Just something else to consider.

-Mark

 

[load]

again bob the typical "riflemans rule" is not my math, nor MY bad advise. it is the "typical" accepted idea thats taught across the country. all three formulas are close and NONE are exact. its the idea that needs to be understood all calculations should be verified and logged. gun)

 

[Buffalobob]

all calculations should be verified

Shawn Carlock did that for us. His ability with a rifle at extreme ranges is phenomenal. That is why people like Berger and Nightforce/Exbal ask him to test their theories and products.

 

[WildRose]

The knowledge base of shooting uphill and downhill has constantly improved in the nearly decade this forum has existed. I merely hate to see an internet wonder dispensing advice that we have discredited long ago.

And where we are at the moment is exactly as you said



No one who regularly kills animals at 1K and beyond will accept anything that looks like a one MOA error yet the internet wonder concludes.



That is an unacceptable error bracket for any single component of long range shooting when there are so many other sources of error that have to be accounted for.

Yep. If the sum of all errors is less than 1MOA you are in pretty good shape. However much like when building a gun it's the accumulation of errors each within tolerance, that can add up to a real problem.

 

[yobuck]

as for whitetails not being found where serious angles are involved.
that would depend on location for the most part.
many western whitetails seem to be found in stream bottom areas.
i can assure you thats not the case in the steep mountains of the east.
serious angles can be encountered and need be compensated for.
the fact is weve been doing that somewhat successfuly for decades.
no doubt better information and equiptment is now available.
fortunatly whitetails dont usually run off after the first shot.
thats where the use of an experienced spotter comes into play.
whether it went just over his back, just under his belly or just off his ***, it
makes little difference.
compensate and get another one over there right now.
sort out the technical stuff later over liver and onions and some adult beverages.

 

[MontanaRifleman]

as for whitetails not being found where serious angles are involved.
that would depend on location for the most part.
many western whitetails seem to be found in stream bottom areas.
i can assure you thats not the case in the steep mountains of the east.
serious angles can be encountered and need be compensated for.
the fact is weve been doing that somewhat successfuly for decades.
no doubt better information and equiptment is now available.
fortunatly whitetails dont usually run off after the first shot.
thats where the use of an experienced spotter comes into play.
whether it went just over his back, just under his belly or just off his ***, it
makes little difference.
compensate and get another one over there right now.
sort out the technical stuff later over liver and onions and some adult beverages.

I was just having a little fun with that comment.... and let's take a look at what I actually said....

.....you will not find them very often in places where angle shooting is a factor.

And that is quite true. I'm originally from PA and hunted the Appalachians and also spent 4 years in Plattsburgh NY, and hunted the Adirondacks as well. I've been through most of, if not all the Appalachian states, from GA to Maine and am very familiar with the Adirondacks and White Mountains. I would say that W.VA probably has the steepest slopes, valleys and hollows on average in the Appalachian range. The Eastern mountains are much more worn down and forested over than the Rocky's and other Western ranges. You'll be hard pressed to find many, or even few, LR 30* angle shots on whitetails in those mountains. Yeah sure, you might find a couple, or even a few, but they are rare. Also, most of the best whitetail hunting will be around farm country.

Anyway, like I said it was just a lite comment leading into my main point which was... when angle shooting, bullet path through the body and vitals should be considered as well

 

[Michael Eichele]

What most shooters dont understand is why we cannot just take the bullet drop and multiply it by the cosine of the angle.

The reason you cannot do this and expect great accuracy is because there are OTHER angles at play and not just ground youre shooting on. It is for this reason that you have to take the 'bore line' drop and multiply that by the cosine of the angle. This value gets deducted from your 'corrected' bullet drop (drop from zero).

Think about this:

You're rifle is zeroed at 300 yards. You are firing on perfectly level ground. Is your rifle barrel level? No matter how fast or flat your rifle is the only way to hit your 300 yard target is to tilt the barrel up. Your bullet then rises higher than your crosshairs when aimed at your target. If you agree please read below.

Now think about this:

You take that same rifle and fire it at a target 1000 yards away that is 90 degrees straight up. Can you multiply the range by the cosine and expect to hit your target? No. The cosine of 90 degrees is 0. You would be trying to shoot for 0 yards. How do you bring your scope in alignment to shoot 0 yards? If you raised the scope above the rifle so high that it could look down at the muzzle for a 0 yard shot, how would that benefit you at 1000 yards? IT WOULDNT. Even if you took and multiplied 1000 yards by the sine of 90 degrees which is 1.0, could you zero your scope and just aim for 1000 yards? No.

If you zero your rifle for 1000 yards on a level surface and then switch back to that 1000 yard target straight above you, why will it hit high, or in this case high in relation to the target but really behind you? This is because the rifle barrel is tilted 'up' remember? In this case, the barrel is NOT 90 degrees up. It is over 90 degrees. As you fire, the bullet crosses your line of sight and just keeps on going behind you. Remember gravity? This is how gravity affects your bullets in this context. That said, the only way to hit that 1000 yard target 90 degrees up is to get the forces of gravity to act soley on the front of the bullet. The only way to do that is to adjust our sights in a way that will move our barrel to 90 degrees straight up.

The above is the most extreme example but it shows why multiplying the range by cosine does not work. However, if you apply Sierra's formulas, you will DRILL that target.

So yes, there are 3 methods. 2 are useless for extreme angles and ranges, the other is spot on. Can multiplying the cosine by the bullet drop work in some cases? Absolutely. In most cases in fact. When you start hunting goats, sheep and other rugged mountain critters though, you had better use the right method.

M

 

[Michael Eichele]

eventually you get to a point were none of this math will work the same for up/down hillgun)

If you apply the correct math, I beg to differ. You could rotate the example below so that it was 90 degrees straight down. The math works the same. Take the boreline drop times the cosine of the angle and deduct it from your corrected drop, adjust accordingly and you will hit your target. You will not be able to adjust your scope dials for a perfect hit. You will still have to aim low at 1K at 90 degrees but you would be close enough to hold under. You could typically get within 1-1.5 MILS or roughly 4 MOA. Using a MIL or MOA reticle, you would simply adjust your dials to the best setting (which would typically be for a 100 yard standard zero) and hold under for the value calculated.

 

[BuckSnort]

If you apply the correct math, I beg to differ. You could rotate the example below so that it was 90 degrees straight down. The math works the same. Take the boreline drop times the cosine of the angle and deduct it from your corrected drop, adjust accordingly and you will hit your target. You will not be able to adjust your scope dials for a perfect hit. You will still have to aim low at 1K at 90 degrees but you would be close enough to hold under. You could typically get within 1-1.5 MILS or roughly 4 MOA. Using a MIL or MOA reticle, you would simply adjust your dials to the best setting (which would typically be for a 100 yard standard zero) and hold under for the value calculated.

I don't see how it is physically possible that this graph is true... How can it be off just as much shooting straight up than it is while shooting on a flat plane.. I understand what you're saying about the angle of bbl vs. line of sight but I think somewhere the physics of gravity pulling straight down on a horizontal distance is lost... I'm no physics major but I just don't agree with you're numbers... I do agree that it will be off shooting straight up but no where near the same amount as a 0 degree angle..

 

[Michael Eichele]

I do agree that it will be off shooting straight up but no where near the same amount as a 0 degree angle..

Let's say for a moment that you are right. The physical path of the bullet is in reality a different measurment compared to shooting at 0 degrees.

The point is, if you use this formula, you will make a hit. You have to change the angle of the barrel. The proper way to get the angle right is to apply the principal in the graph.

The formulas used to make a 1000 yard hit at 0 degrees dictated how much the rifle's barrel is tilted up. If the bullet drop from bore line is 300" at 1K and you compensate for 300" to make a hit dead on and then shoot 90 degrees straight up at a target the same distance away, you HAVE to undo step by step 100% whatever you just did to compensate for the 0 degree shot. In other words, mathematically you will be 300" high and need to come down 300" to make a hit. 300" up for a level shot, 300" down for a 90 degree shot whether the bullet is 100 or 300" above the target. A 90 degree shot is about angles and getting them all correct, not bullet drop.

OR, forget inches for a minute. You compensate 125 clicks in your scope to get the barrel tilted up properly for a 1000 yard 0 degree shot. To make the same shot 90 degrees above you, you have to come back down an equal amount of clicks. That is 125 clicks.