Rule of Thumb for Shooting Down Hill

[vancewalker007]

Hi everyone. Got back earlier this week from hunting CO 2nd rifle elk season in GMU 681. Took a cow early on but the bulls were scarce especially given the high winds. At dusk on Weds I had a 5 pt bull appear at 503 yards quartering to and since he was close (30 yds from) a fence (private ranch on the other side), I aimed high on the shoulder (after dialing my Gunwerks 7mm RM shooting 168 gr VLDs to 500 yds) & gently squeezed. My spotter called the shot right over his back. The bull promptly moved off into the timber (not presenting another shot), jumped the fence and minutes later was shot on that private ranch. One more data point, the bull was 10 degrees downhill from me and I had a solid but not perfect rest.

My question is, did I just muff the shot high or should I have dialed a shorter distance on the Viper PST? Do you have a rule of thumb for shooting at high or low angles, like "for 10 degrees, reduce the distance by 10%"?
Thanks for your time & advice!

If 503 yards was your line of sight range and your shot angle was say 10 degrees (which is small) to then your true ballistic range was 495 yards. So you would be slightly high with your dialing to 500.

 

[greenejc]

Years ago I watched when Best of the West (if I remember right) did some uphill and downhill shots to see how much it could cause for error by dialing for the shot that the rangfinder said. They learned that the farther away the shot is, the less the angle will be. In all of their shots they took for the show, none of them ever missed by more than 4" because of the uphill or downhill shot. They said that when it comes to only that variable, it should never be enough to make you miss or have have a really bad shot on a big game animal.

Yep, on a deer or especially an elk, center-mass will still put it in the boiler room out to about 600-700 yards if your range is right unless its a really steep angle.

 

[kfreeze]

Yep, on a deer or especially an elk, center-mass will still put it in the boiler room out to about 600-700 yards if your range is right unless its a really steep angle.

They tried to find really steep angles to shoot at, but everytime in the real world, as distance got greater the angle became less and didn't change much. They said that there just weren't many places they could find in the real world that the incline and distance would allow for them to take a shot to see it.

 

[greenejc]

If 503 yards was line of sight the true ballistic range was quite a bit less if the angle we was anything at all. If it was 20 degrees, then



If 503 yards was your line of sight range and your shot angle was say 10 degrees (which is small) to then your true ballistic range was 495 yards. You were aiming about 8 yards high or about 57 MOA high. You cannot use line of sight alone to hunt with.

He was actually shooting a 503 yards, which is a drop of around 48 to 52 inches in a 7 rem mag, maybe less if the B.C. is in the .6 range. That would have been about 9 to 10 moa at that distance, which is what he dialed in, if you read his information. He dialed in for a 500 yard drop, using I'm sure the GunWerks propritary scope dial for his rifle and load. Ranges are marked on the elevation ring, and they're pretty exact. I'm going out on a limb here, but I'll bet he has dialed in distance before using his scope and hit what he aimed at just fine. Since his spotter said he hit just over the elk's back, I'm pretty sure the range was pretty close to exact. I'm pretty sure if he had dialed in 57 moa, the spotter would have never seen the impact of the round(actually, I know he wouldn't have.). He just aimed a little high because he tried for the spine so he wouldn't lose a wounded animal to private land. Guaranteed the rancher would have charged him to retrieve it, even though it would have died right next to the fence on private land. He was just trying to make sure it didn't travel that 30 yards or so.

 

[greenejc]

They tried to find really steep angles to shoot at, but everytime in the real world, as distance got greater the angle became less and didn't change much. They said that there just weren't many places they could find in the real world that the incline and distance would allow for them to take a shot to see it.

A few canyons and buildings over 30 stories, and then only to around 500 yards. After that, angles flatten out, so all you have to worry about is angles of around 30 degrees or less (mostly less). The difference is negligable at distances under 600 yards when trying to hit a 14" to 20" circle(kill zone on deer and elk). He just shot over due to his aim point. It happens to just about everybody. I'm sorry he lost the elk, though.

 

[big johnson]

check out the charts for 3d archery shooting

 

[dfanonymous]

They tried to find really steep angles to shoot at, but everytime in the real world, as distance got greater the angle became less and didn't change much. They said that there just weren't many places they could find in the real world that the incline and distance would allow for them to take a shot to see it.

It's true. There isn't many places. I'd like to see some of you actually try to shoot or even build a shooting position at 35 degrees on a hill side.

There is consideration for para/military though. The use of such extreme angles come with shooting from a helicopter, or up into a tall man made structure. As was mentioned, these aren't usually "long ranges."
Beyond that, it's rare, I'll say again, rare, to be forced to shoot around or beyond 35 degrees in real world application.

 

[shane holt]

bullet drop is only affected by HZ distance . once you establish that, apply your drop correction from your sight in.

 

[436]

As has been said in one way or another, it's about the gravity effect on the projectile not so much distance in up and down angles, which makes the distance shorter.

 

[StanB]

GMU 681...503 yards....10 degrees downhill....7mm RM shooting 168 gr VLDs...Gunwerks dial

You may not have muffed-it all that bad. Running some numbers at 2950 fps for that Berger gives a nominal 36" drop @ 500 at high elevation & 30F. With -10 degrees slope, 35" drop, so only an inch of difference, < 1 click. If the slope was more like -18 degrees, your at 33" drop. If the Gunwerks dial was printed for lower elevation, could add 1". So total static error of 3-4". With a high spine hold, it wouldn't take much of a wiggle to miss at 500 yards with a 3" elevation error on the turret.

 

[HappyGVM]

Thanks for all the advice and feedback. I don't mind admitting a mistake and am happy to incorporate the constructive feedback to shoot better next time. I will definitely re-read the directions on my range-finding binos because I thought it did compensate for angle.

Oh & I was hunting south of Mosca Pass about 4 -6 miles. Great Sand Dunes national park is the western boundary for the unit.

 

[greenejc]

It's true. There isn't many places. I'd like to see some of you actually try to shoot or even build a shooting position at 35 degrees on a hill side.

There is consideration for para/military though. The use of such extreme angles come with shooting from a helicopter, or up into a tall man made structure. As was mentioned, these aren't usually "long ranges."
Beyond that, it's rare, I'll say again, rare, to be forced to shoot around or beyond 35 degrees in real world application.

Yes, and at short range, the change in impact is neglegible. It wouldn't be enough to miss your shot. Helo shots are totally different world.

 

[greenejc]

You may not have muffed-it all that bad. Running some numbers at 2950 fps for that Berger gives a nominal 36" drop @ 500 at high elevation & 30F. With -10 degrees slope, 35" drop, so only an inch of difference, < 1 click. If the slope was more like -18 degrees, your at 33" drop. If the Gunwerks dial was printed for lower elevation, could add 1". So total static error of 3-4". With a high spine hold, it wouldn't take much of a wiggle to miss at 500 yards with a 3" elevation error on the turret.

Exactly. That, coupled with a high point of aim and maybe a little shot variation could easily generate the miss.

Thanks for all the advice and feedback. I don't mind admitting a mistake and am happy to incorporate the constructive feedback to shoot better next time. I will definitely re-read the directions on my range-finding binos because I thought it did compensate for angle.

Oh & I was hunting south of Mosca Pass about 4 -6 miles. Great Sand Dunes national park is the western boundary for the unit.

I know the area. I haven't hunted it.

 

[Chadp82]

Thanks for all the advice and feedback. I don't mind admitting a mistake and am happy to incorporate the constructive feedback to shoot better next time. I will definitely re-read the directions on my range-finding binos because I thought it did compensate for angle.

Oh & I was hunting south of Mosca Pass about 4 -6 miles. Great Sand Dunes national park is the western boundary for the unit.

Awesome attitude! I once missed a really good deer at 250ish on a steep uphill shot. I did recognize my 200 yd zero was about where I should be. Even though the math is right, the steep shots aren't the shots we practice often (or at least not me). Sucks to do when you know it was a makeable shot, but it happens.

Things happen in the field differently than the bench. Sucks to miss a shot, but it happens to most of us from time to time.

My lesson learned from missed game, is I usually rushed the shot. I still get an element of buck fever and excitement when the time comes and know I need to calm my breathing down. As friends of mine begin hunting, I advise them mistakes are made. Learn and remember what what went wrong so it doesn't happen again. I have messed up…. Not just shots, but wind, noise, and other things over the years. Poo happens.