Spatsizi final couple of details...sighting in..

[srupp]

I have gotten down to the finale couple of details for our Stone sheep hunt...I am going to see if I can get some bullets custom reloaded..i will need to pull a favour in for that..hmm I owe EVERYONE so this might be difficult...:cry:

I have decided to go with 140 grain in my .270 with Hornady BTSP chronographed @ 2950...tables list +1.6" @100
200 - dead on
300 -7.1
400 -20.5

HOWEVER..:mrgreen: I am going to sight in for + 3" @ 100 yards...Im thinking out loud here..the vital area of a ram..or billy or buck is about 14" so to eliminate guesses or holdovers..if I hold for the center of the chest I can be no more than 5 " high or approx 5" inches low....so the bullet will be approx 4 " high @ 200 yards...and never will get higher than this..it will then be on the button @ approx 300 yards and approx 8.5 " low at 400 yards... sooooo by holding dead center for most shots will be AOK..and for the long shot with the +3" @100 yards a line up on the back will drop that same bullet into the vitals @ 375-400 yards..= no hold over.
And yes Im not going to discuss wind effects....

Feedback gentlemen....fire away...

Steven

[WoodOx]

Sounds logical to me. I do the same sort of thing, usually sight in 1" high at 200 yards. I really shy away from anything over 300 yards. Took 3 hits to bring down a deer last year at over 300 yards, which I really really dislike. This is just my opinion, but on my sheep hunt this year I am planning on keeping shots under 250.

Your ballistics info sounds right though - I would personally hold a lil low at 100, and a little high at 400 with the info you provided. At 400 yards, wind and various other variables can play on that bullet's performance.

best of luck! what time of season are you heading out?

[StoneChaser]

Steven, your numbers are off a little, so I ran them on my ballistics program (I've used it for years and trust it). I always use a 8" maximum PBR for my big game rifles (bullet never goes higher than 4" along the flightline). I always view the vitals more the size of a 4L milk jug (to be safe).

140gr BTSP @ 2950fps

8" PBR (no higher than 4" at the highest point):

100yds : 3.29"
150yds : 4.0"
200yds : 3.5"
250yds : 1.69"
300yds : -1.43"
350yds : -6.10"
400yds : -12.42"
450yds : -20.47"
500yds : -30.33"

This will sight you dead on for 280yds and you'll not fall out of the 8" killzone until 330yds!

At 400 yards simply hold a few inches into his body (to eliminate shooting over him) and you're in the money!

You'll hear the arguements about shooting high...but if 4" in height (at 150yds) makes a guy miss, he's in trouble anyhow.

[srupp]

Thanks Guys..Im going to sit down with a coffee and look over the #'s

Steven

[Sitkaspruce]

Steve

Great bullet choice. That is what I use and I have always sighted my gun in at exactly 3" high at 100. S/C info is dead on with mine. A little hint, print out this info and laminate it so it is waterproof, then carry it with you, just in case you forget the info in the heat of the moment. I have killed goats and sheep out to 375 yards and never had to "Hold over the back" with the gun sited in at 3" high.

I also agree with S/C in that if you are worried about the 4" at around 150, then you are already shooting high, and that hitting something at 300 yards is the least of your worries.

PM me if you need a load for your bullet of choice. I have mine at 2975 fps, 3/4" group for 5 shots. Of course this is out of a Winchester featherweight, not a Browning:mrgreen:, but who knows, it might just work for you as well.

[srupp]

AGAUCHER sorry didnt read your question..we were going in for Sept..best time for rams to be moving around rather than the heat of August....HOWEVER I am a Paramedic and holidays are selected waaaaaaay in advance of any draws..so we are headed in for August...

Will do the best we can..and IF nothing I may consider hiking back in ...Sept???

Steven

[WoodOx]

Sounds good Srupp. Best of luck!

[Brambles]

Might be a little confusing shooting at steep angles while having a rifle sighted 3" high at 100. Just a thought

[Stone Sheep Steve]

Here's a good read for uphill/downhill shooting.
http://www.wildsheep.org/magazines/article_uphill_shooting.htm

or here it is...from Grandslam/Ovis


UPHILL/DOWNHILL SHOOTING REVISITED
Note: A trajectory chart will open in a new window.
Pressing "ctrl" & "r" at the same time will reload it
In the Winter 2001 issue of GRAND SLAM, we featured an article about uphill/downhill shooting. The article was a collection of information by various GSC/Ovis members. There is still some confusion out there as to what is really involved in uphill/downhill shots, so here is a theory recap of angle shooting and how to prepare yourself for the shot.
Gravity From a Shooter's Perspective
First, the context of what is meant by "gravity" in this article needs to be clarified. Of course, gravity affects all things on earth. If you shoot a bullet straight up in the air, it is going to come down because of gravity. If you shoot a bullet across level ground, it is eventually going to land somewhere because of gravity. In the scientific sense, gravity always affects a bullet.
However, for this article, think of gravity only as it affects the "curve" or "arc" of bullet's path. More gravity will produce a path that curves downward more, less gravity will produce a straighter or "flatter" bullet path. The other aspects caused by gravity, such as time of flight, are insignificant when applied to exterior ballistics.
Barrel-Scope Relationship
To understand uphill/downhill shooting, you must first understand that your line of sight and barrel are not parallel. If you are like most rifle hunters, you sight your gun in to shoot several inches high at 100 yards. To accomplish this, your barrel must point higher than your scope’s line of sight. As the distance increases, your barrel will point proportionally higher and higher. The figure below illustrates this:
http://www.wildsheep.org/magazines/images/articles/uphill_shooting_bore_line.gif
Using the bullet and load table at the bottom of the page as an example, to achieve a 300-yard zero, the barrel must point almost 18” high at 300 yards. Why? Because at 300 yards, gravity is going to push the bullet down about 18”. Thus, you will be zeroed at that distance. At 500 yards, the barrel actually points about 31" higher than the line of sight.
Horizontal Distance is What Matters
By now, most people understand that gravity only affects the horizontal component of a bullet's path--whether or not you are shooting uphill or downhill. The steeper the shooting angle becomes, the less the horizontal component of the angle becomes, and the less chance gravity has to "curve" or "arc" a bullet's path. The examples below illustrate the horizontal components of an uphill or downhill shot:
http://www.wildsheep.org/magazines/images/articles/uphill_shooting_angles.jpg
The less chance gravity has to affect your bullet (i.e. less horizontal distance traveled), the flatter your trajectory becomes. In other words, your bullet's path is closer to where you barrel is actually pointed.
By now you might be thinking, "Ok, so at 500 yards at a 60-degree angle, my bullet is affected by gravity just the same as 250 yards on flat ground, so I would aim like it was a level 250 yard shot, right?" WRONG! This is the a myth in uphill/downhill shooting. The reason is very simple. Forget about gravity for a moment, remember, you are actually shooting at 500 yards and your barrel is pointed much higher from your line of sight at 500 yards than 250 yards.
In order to accurately compute the uphill/downhill trajectory, we must factor in BOTH the shot angle and the barrel-scope relationship.
Putting it All Together
Now that we understand the factors of angle shooting, how do we figure out the numbers for our individual gun, load, and zero? The answer: A ballistics program that computes uphill-downhill bullet paths at different angles. There is no other way. You can either purchase custom made cards for your particular load (check out www.ballisticards.com) or, if you have a computer, you can purchase a ballistics program. Sierra Bullet's Infinity ballistic program is excellent for this purpose. Be careful, as some other programs will give you the angle measurement is Minutes-of-Angle (MOA), and the only way you can use that data is to manually adjust the dials on your scope. The way you use a ballistic program is to set up the load and zero parameters for level ground, then see how the trajectory looks at different angles, keeping those same load and zero settings. Once you run all the numbers, you need to make a "cheat sheet" and keep it with you in the field.
Measuring Uphill-Downhill Angle
On high-angle shots, accurate angle measurement is critical. There are many tools available, with several being mentioned in the Winter 2001 issue of GRAND SLAM. There is one more tool that should be mentioned, and it is called the Slope Doper. It looks like a protractor, but the scale is positioned differently to allow you to sight down the straight edge. A wire hangs down by gravity and will give you a good estimation of the angle.
NOTE: The decimal numbers on the Slope Doper are for MOA calculations--if you adjust your scope dials when hunting you would use these; if you use the "hold over" method, you would ignore these and just look at the degree measurement.
http://www.wildsheep.org/magazines/images/articles/uphill_shooting_slope_doper.jpg
Reading Between the Lines
Does angle make a difference? You bet! One of the first things you will notice when you build your "cheat sheet" is that your bullet will be shooting above your point of aim at high angles--even at very long ranges. Instead of our example bullet dropping almost 4 feet at 600 yards, the bullet now shoots high by over two feet at an 85-degree angle. That's a difference of six feet! How could it shoot higher than your line of sight? Remember, your barrel is pointed much higher than your line of sight. To be more specific, our example barrel points about 31" high at 500 yards. So, at an 85-degree angle (only a little bit of gravity affecting the "arc"), it makes sense that you would shoot about 25 inches high.
Also notice that at high angles, accurate angle estimation is crucial. Say you are hunting desert sheep and a big ram is below you at 400 yards. The ram looks nearly straight down and you think the angle is 75 degrees. Well, if the angle was actually only 60 degrees, you would have missed your point of aim by 8 inches.
Remember the myth that you can just "triangulate" the horizontal distance and aim as if you were shooting at that distance? Look at the trajectory table (opened in a new window). At a 60-degree angle at 400 yards, our bullet strikes 7.3" high. If the myth was true, the 400 yard 60-degree angle trajectory would equal the 200 yard level ground trajectory. Comparing the two numbers we see that our bullet shoots 3.7 inches higher on the 60-angle shot. That may not seem like much, but why not be right the first time around? At further ranges or higher angles, the difference becomes even more significant.
Take a moment to study the chart (opened when this page was loaded). Even if you shoot a completely different caliber or load, the trajectory is going to look fairly similar. There are more charts posted below for you to reference. Good luck and good shooting!
More Uphill-Downhill Charts:
.264 120 gr. J-36 Bullet @ 3,260 fps, zeroed at 300 yards (http://www.wildsheep.org/magazines/images/articles/264_chart.gif)
.308 180 gr. Nosler Partition @ 2,900 fps, zeroed at 273 yards (http://www.wildsheep.org/magazines/images/articles/30_cal_180_partition_2900_fps.GIF)
.338 225 gr. Barnes X @ 3,250 fps, zeroed at 200 yards (http://www.wildsheep.org/magazines/images/articles/chart_225_gr_barnes_x.GIF)
.284 175 gr. Rem. Core-Lokt @ 2,860 fps, zeroed at 200 METERS (metric data) (http://www.wildsheep.org/magazines/images/chart_7mag_175_gr.GIF)


SSS

[todbartell]

you could read all that until your eyes bleed out, or you could get one of these...:mrgreen:

https://www.nafan.com/hosted/graphics/products/1/200/bushnell-elite-1500-arc-mossy-oak-laser-rangefinder-205101.jpg


remarkable technology accounts for terrain angle to give you an accurate “shoots-like” distance – all with the tap of a button. Rifle mode even tells you where to hold.http://www.bushnell.com/arc/1500warc_1.html

[Stone Sheep Steve]

So I wonder what info it'll give you for a near verticle 400yd shot??

SSS

[boxhitch]

I've looked at the Bushnell arc -
- It works to 60 degree angle
- rifles are sighted to 0 @ 100 yds.
- shooter is presumed to know what 47" of holdover looks like at 500 yds.

[todbartell]

holdover?? quit guessin and hold dead on :mrgreen:

http://www3.sympatico.ca/milcun/turret.jpg

[Gateholio]

So I wonder what info it'll give you for a near verticle 400yd shot??

SSS


Hold low........:twisted::twisted::twisted:

[Elkhound]

Hold low........:twisted::twisted::twisted:

Words of wisdom from experience:wink:

[Gateholio]

Words of wisdom from experience:wink:


Sad, pitiful, but true...:mrgreen:

[Flinch]

On my Leuppy 3-9x40 the distance between the center of the crosshair and the top of the post is about 12" at 400 yds when on 9x. Not a coincedence that I am sighted in to hit 12" low at 400 so I would just use the top of the post for 400 yd shots. I also like to use clear tape to apply a small piece of paper with my trajectory and uphill/downhill conversions to my stock.