Thoughts - Squirrel, angle shooting, and ammo FPS

Let me start off by tell you about last year's squirrel season.

Usually I carry a .22mag running 30gr hornady vmax ammo, just in case I came across a predator or varmint along the way. Last year I thought to go back to the .22LR. Since I devoted myself to CCI Standard Velocity, I figured I'd "Paco tool" a couple boxes of CCI SVs into hollowpoints as to keep all my data and adjustments the same as my paper punching, plus having a bulk inventory of SV, the chances of running out are slim and more economical too.

As my paper punching data starts at 25 yards, I figured a mildot holdUNDER at 10 yards, thinking that most of the squirrels I harvest are out of trees that 10 yards "on the flat" would get me on those critters (which up a tree, is sometimes no distance / just straight up). As my optic is SFP, I figured if I kept it on the same magnification, I'd be fine.

The first day 2011 came and went, missed everything. Not one hit. I'm not the world's best shooter, but able to multiple hit dime sized targets at 50 yards and 20 out of 25 shots at 200 yards in 6"--- but missed every squirrel up the tree, and usually missed high. Squirrels that I spotted at the base of the next few trees over....missed low using the same holdUNDER. Just a bit further, around 15 yards. Getting frustrated, I went back to the .22 magnum, with plenty of bag limits taken, and a lot less ribbing from my brother in law. He's usually my squirrel hunting partner and his ribbing about me not being able to hit something 10 yards away after all the longer range .22 stuff I do was a bit embarrassing.

So now the 2012 season, last year's situation was still driving me crazy, so I figured I'd give the .22LR another whirl with the SV ammo. I went back to the range to make sure my .22LR "squirrel hunting zero" was good, but this time at 15 yards. Same thing, missed every squirrel I shot at. Being frustrated, I thought about the fact that my .22 magnum is doubled in FPS / flatter shooting, and thinking back to my archery days about angled shots, the arc of the arrow, and the point of aim that has to be adjusted...well I had a "AH HUH!" moment.

So I found a tree that had a few small blemishes up and down the trunk (for the tree huggers, the area is slated for construction, the tree was a dogwood of no commercial value) about 15 yards out, took a few shots toward the base, dead on hits. Then started to move up the tree. The higher I went, the higher the point of impact (POI) from the point of aim (POA), even from 15 yards out. At the highest point of the tree, as much as 3" above the blemish I was aiming at. Every shot, even just a few feet higher, resulted in a different point of impact.

Every time I compensated on a squirrel thinking I was now dead on for the next one, the POI / POA was changing depending on how high the squirrel was. Add that to being at a different distances away from the tree, which I also tried. The POI/POA also varied depending on how close or far away I was from the tree, as the angle changed. No wonder I missed so many squirrels.

We all know how cosine / angled shots with centerfires at longer distances plays a big part on if your going to hit something precisely. The flatter shooting the rifle / cartridge, the more less the difference when taking a shot at elevated or declined targets.

I didn't think this was such a big deal with rimfires, after all as a young-un, I shot a good share of squirrels not worrying or even knowing about cosine, POI/POA, etc. Seen a squirrel, aimed dead on, 1 less squirrel. Plus back then, most of the ammo one used was High Velocity. At the time I didn't know what standard velocity or match ammo was nor was it popular or available through most outlets.

So I grabbed some Fed Bulk 36gr high velocity hollowpoints today, established my 15 yard "squirrel hunting zero" (which on a side note equals the SV zero at 25 yards, but hitting 1" left). So making the windage adjustment, was dead on at 15 yards. I did the same drill as before on the blemished tree. 15 yards flat, then moved up the tree. From the base of the tree graduating to about 30 yards up the hits did increase in height away from the point of aim, but soooo much less than with the standard velocity. Well within the size of a squirrel's head, I'd have to guestimate only about 1/2" difference from the base to the top of the tree compared to the previous 3" swing with standard velocity. At different distances away from the tree, the high velocity was also more forgiving. Thus I believe the reason I took more squirrels out of trees with the .22 mag than with .22LR using standard velocity ammo.

So just to "proof" my AH HUH moment, I went to a series of culm dumps (coal mining waste mounds) just down the road, and found one that had several trees growing from the center. I did just the opposite...zeroed in on a blemish at the TOP of the tree approximately the same height and approximately 15 yards away from the crest of the mound, then shot downward until I reached the base, both with SV and HV. The standard velocity again showed a much higher difference than the high velocity, and although one would think the hits would be lower (the shot being opposite from an uphill shot), the hits were still high, but not as much with both the HV and SV, with the HV again being more forgiving.

Again going back to archery, this can explain it better than I ever could:
http://www.kingsmountainarchers.org/...gle-shots.html

Of course the effect is much more pronounced with the slower moving and higher massed arrow, but the principle remains.

http://www.chuckhawks.com/shooting_uphill.htm

http://www.firearmssite.com/shoot_uphill.htm



So when it comes to severe angled shooting with .22LR some things to consider:


1. Standard, subsonic, match velocity - more effect on the point of impact as the angle increases from the shooter to the target. Due to the greater arc of the trajectory just like an arrow out of a bow and more dramatic with slower FPS ammo.

2. What you may be able to compensate for at 5 yards shooting almost straight up will be different even at 10 or 15 yards as the angle changes.

3. If shooting at an upward target, aim low. If shooting at a downward target, aim low, but not as much.

4. As squirrel hunting goes, rarely do they give you enough time to do the math to pull off a good severe angled shot using SV, nor is it really value added to do the math anyway.

So there are some thoughts...though standard / subsonic / match velocity ammo has it's place and advantages on the target range, when it comes to hitting targets that are scurrying relatively level to you, 60+ feet above you in a tree, or 60+ feet below you in a ravine, high velocity offers more consistancy of hits and more game in your bag.

Good info tanks,

Dean

TP, you did what some out hunting alone would not think of.....and that is "burn" a few rounds at those angles where the game is, and not just at a few tin cans straight down the path!! Nice post and some good thoughts for being out in the field.

Thanks

One thing not mentioned, and that I wonder about is parallax. Is your scope a rimfire scope? Is it a variable objective type scope? If not a rimfire, the parallax is usually set for 100yds, and if a rimfire the setting is usually for 50yds, not 15. In either case you may have a parallax issue being more the culprit than the angle.

Here's why.
Bullet and arrow trajectories are controlled solely by gravity. Gravity ONLY affects the flight for the horizontal distance. If the base of the tree is horizontal to you, and it is 15yds away, and the tree goes straight up from there, in other words not leaning to or from you, then the horizontal distance will always be 15yds. That applies to either up or down.

If you look at a range finder and the tree shows 24yds when looking at a 45 deg angle, but the base is still only 15yds away, the bullet trajectory is still 15yds. Your shots should be dead on at all points, that is why I feel it's a parallax issue, not an angle issue.

The same applies to arrows by the way. If I am shooting from a treestand 30ft up a tree, and the deer passes 10yds from the tree, my rangefinder will show about 18yds, but I use the 10yd aim because the 18yd aim will go over his back. Trust me I have been down that road.

adjustable objective down to 10 yards, also tried 15, 20, and 25. wasn't a parallax thing.

Quote:

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Originally Posted by handirifle

Gravity ONLY affects the flight for the horizontal distance.

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I would disagree with you on that statement, or I perhaps I am misinterpreting your statement.

Acceleration due to gravity affects an object solely based on the time that object is subject to the acceleration of gravity.
The acelleration due to gravity is a constant 9.8 meters/second². The only variable is the amount of time the object is influenced (moved) by the earths gravitational pull. For every second a bullet is in the air, it is accellerated 9.8 meters per second toward the earth regardless of how far horizontally it travels in that time. In an ideal world with no other forces acting on the bullet, if you shoot it straight up or shoot it at the horizon, it still accelerates (because of gravity only) at a rate of 9.8 meters/sec² toward the earth.

thomae
I think we are saying the same thing there, pretty much. The difference in my thinking, is the compensation comes with the bullet traveling in vertical manner, especially in downhill mode, the bullet velocity is actually aided by gravity, thus reducing the flight time somewhat.

As for the straight up part, I seem to disagree, in that the bullet path will come down the same as horizontal, ONCE it starts down, but the time it takes to go up is added flight time that the horizontal shot does not get. The vertical bullet, will most likely reach its top altitude, the same time the horizontal shot hits the ground. but then it has to come down.

In either way, I feel there is no way his bullets POI should change that much from such a short path.

Yup, I think we agree.

I was not saying that the horizontally shot bullets would hit the ground at the same time.
What I was saying is that once out of the barrel, in a frictionless and ideal world, both bullets accellerate (due to gravity) at 9.8 meters per second per second toward the ground.

Therefore, after one second, the vertical component of velocity in the bullet shot horizontally (which was zero when the bullet left the barrel) is now in the direction "down" at 9.8 meters per second.
After two seconds, the vertical velocity of that bullet is "down" at 19.6 meters per second.
and so on and so on until it hits the ground.

For the bullet shot straight up:
One second later the vertical velocity is still "up," but it is 9.8 meters per second less than it was when it left the barrel.
For each second after that, you can subtract 9.8 meters per second from the vertical velocity until such time as the vertical velocity reaches zero.
After that, you add 9.8 meters per second in downward velocity for each second the bullet is in the air, until such time as it impacts the ground.

In this example the two bullets will impact the ground at vastly different times, but the accelleration due to gravity will have been exactly the same on each bullet.

We'll have to get together over a beer and talk about this someday.

I love math in real life!