Serious Hunting Question

[JOHNNY QUEST]

Ok I am dead nuttt at 22yds. shooting level... Now lets say I'm using my AA S410 C and a creature of interest lands 20 ta 25 Yds. up in a tree.. Well it doesn't have to land , it may just appear... Ok now I am shootin the same distance but AT  a 45+ deg. angle up... what the heck do I do.. Its Eluded me for quite some time and I can't figure it out.. I know gravity has a thing to do with it.   Any help would be much apreciated...

[Timmyj1959@yahoo.com]

Hey Randal,, Tim here! I have wondered bout that too. At those close ranges I have not noticed any significant poi. change shooting downwards (in the mountains) or up into the trees. Im shure there is some deviation though. I have read of significant effects at longer ranges though. I have noticed BIG changes hunting with my bow from tree stands,, so it only stands to reason the same would apply to some extent with airguns. Im shure one of the more knowledgable folks here will have some good info on this subject. Good question Buddy. Hope all is well. Tim.

[only1harry]

Usually at that close a range (25-45yds), when I aim up at an angle (aka squirrel) I have discovered that the pellet rises so I aim lower just a little to compensate.  I guess it's because the higher the angle the higher the curve is going to be.  Think of it this way.  If we want a bullet or a pellet or arrow, etc. to land pretty far away, what do we do?  We aim up higher at a much steeper angle.  So when aiming up at 40deg. or more, the trajectory changes and the pellet rises within a "short" distance.

Now this is for my Springers & PCP's, don't know about others.  I proved that to myself this summer when I got my 1st Condor which is the most accurate gun I have and has no recoil so there is very little room for error.  I sighted the gun on the ground for 30yds.  I then picked a spot/ring on a tree 30yds out shot up at a 35-40deg. angle.  The POI was almost 1/4" higher repeatedly!  I then picked a target on a tree almost 40yds out and the POI was even higher!  When I shot at a tree 50yds out (and about 60ft up) the POI was about the same as the 30yds on the ground (where the crosshairs were).  So at that point the pellet had started leveling off.  That was with 21gr Kodiaks.  
I then tried the 28.4gr Eun Jins and at 40yds shooting upwards the POI was almost the same as my 30yds on the ground, so it depends on the weight of the pellet.. BUT, at 30yds the heavier EunJin had a lower POI than the ligher Kodiak to begin with, so the behavior was the same.  At 50yds the Eun Jin's POI was a bit lower and understandably so.

Another way to think of it is this.  If you are shooting at a target on the ground or at shoulder level, the pellet usually keeps rising until about ~40yds depending on the velocity & weight of the pellet.  So when you zero your gun for 22yds, even if you were shooting at something on the ground past 22yds chances are you would have missed unless you compensated because the pellet would hit higher.   When shooting closer than 22yds, the pellet will strike lower.  When shooting upwards at an angle, even if it's at 22yds, it's the same as trying to hit something that is farther away, so you have to aim lower to compensate for the rising pellet or taller trajectory.  Make sense now?  Just take my word for it.  Next time you have a nutter up on the tree 22yds out, just aim 1/2" lower and you 'll hit it.  I 've made many shots like on treed nutters inside 30yds.  Send me the tail and we 'll call it even    :emoticon:

[TCups]

Think of it this way:  If your were looking through the scope at a pellet fired horizontally, the further away from the rifle the pellet travels, the lower the pellet would sink relative to the line of sight of the scope the further the pellet travels, because it is falling (actually accelerating) toward the earth.  But, if you shot straight up or straight down, while the pellet still decelerates or accelerates (respectively) due to the force of gravity, it no longer appears to fall relative to the vertical line of sight of the scope.  So, if you shot at 25 yards straight up, then with respect to the point of aim, the point of impact would remain too high for the point of impact you have your scope zeroed for at 25 yards. So you would miss, shooting too high over the point of aim set for a horizontal shot.  Exactly the same thing if you shoot straight down.  To compensate, you must hold UNDER the target with the point of aim to bring the point of impact on target, whether you are shooting up hill or downhill.  How much?  Well, that depends on the angle of the shot and the initial velocity of the pellet, and what range your scope is zeroed for.  If I am shooting up at a steep angle with my springers, I usually aim about 3 inches low.

[expomatic]

Well, if we go back to our Physics 11/12, we can do a vector analysis and determine exactly where our pellet should strike.

To make a long story short, a passive projectile fired at an angle upwards from the horizon will contain a non-zero force component in the y, or vertical, direction. This force works directly against the force of gravity which always pulls straight down.

So, to hit a target that is say, 40yds away and at a 30degree angle, we would need to provide LESS holdover to achieve the same POI for a target that is 40yds away and parallel to the horizon.

[shadow]

The family filled you in nicely Randall It becomes second nature after awhile, one just knows where they need to put the cross hairs. Ed

[ccjr]

Randall:

There's an excellent visualization tool at http://www.arld1.com/ , Demo 21 near the end of the page.

I just (10 minutes) installed the GNU exterior ballistics program, which has an input for shooting angle, but I haven't yet tried it.  There are windows and mac versions in addition the linux I use.

[crazyhorse]

Here is another useful calculator...I've charted some at angle/ranges s I often shoot at with my air rifles....but mine are low angles around 30 degrees..up/down....

http://www.airgunexpo.com/calc/calc_hold.cfm?

[JWC]

I just (10 minutes) installed the GNU exterior ballistics program, which has an input for shooting angle, but I haven't yet tried it.  There are windows and mac versions in addition the linux I use.

There's also a web based version:
http://ballistics.nerdulator.net/index.php

[tjk]

Great topic of discussion here! I had the same problems today with my 'hot-rod' Sierra-Pro shooting at BT's! But the slower Marksman hit the spot every time?!?!?!? Glad we have such knowledgable shooters amounst our ranks!!!! tjk

[ronbeaux]

Aim low, but don't give up the head.

We got shots like that in feild target comps and you always have to aim low or you will clip the edge of the hole and it won't fall. At 22 yards I would range it and then adjust the scope, then I would hold at 0600 just ouside of the kill circle. It would end up either dead center or just below center on a 1/2 inch hole.

In Hernando MS we had shots like that only they were down hill. It was just the opposite.

I tried to read all the math related posts above but it's been 35 years since I had math. The above is experience only.

[longislandhunter]

I follow Eds  (Shadow) advice,,,, I just instinctively aim and seem to do ok.   I won't say I don't miss though,,,, cause I sure do sometimes

Jeff

[crazyhorse]

yep...two ways to go...instinct...or knowing your rifles dope.....

[Timmyj1959@yahoo.com]

Well,, I agree with Jeff,,, like Ed,, Ya just practice before Ya hunt. No fancy numbers/words for me. Ed calls it "Zen",,,, us Hunters deep down know the feeling.  You just have to practice on all kinds of targets & get a "feel" for it,,,,,,,, yep,,, "Zen" is what its called!!  The angle shooting is differant,,,,, most of my sucsessful medium/big game posts I have made here were no acident,, I knew EXACTLY where my pellets were going to hit at pre determined ranges under ideal conditions. ( I push the limits with my "BB Guns at times & I owe it to my quarry to be effective) I have some past posts here that would show that. :p  Its a confidence thing,,, Ed calls it "Zen".  I concur. Good Hunting my Friends,, Tim.

[longislandhunter]

A big part of that "instinctive aiming"  is in fact knowing the dope on your rifle, which of course comes from practicing with them until you are proficient at various ranges.  One can also rely on calculators and mathematical calculations, and that's fine, but for the hunting aspect that I dwell, on where you may only have  a second or 2 to judge the distance and take a shot, it's crucial to be one with the rifle and just "know" where to put the crosshairs....

I"m not knocking the mathematical approach, not at all, it works and it works well, after all it's math,,,, it has to add up correctly    
but each hunter / shooter needs to choose which is best for him / her.  

Jeff