Rangefinder question

ninepointer · Post by **ninepointer** » Mon Sep 17, 2007 10:51 am

I have never used a rangefinder and I have some questions. If I'm up in a treestand, a rangefinder will give me the distance from me to the deer (in other words, the dimension of the hypotenuse of the triangle formed by the treestand, the deer and the base of the tree). But, my crossbow scope settings (20 yd, 30 yd, etc.) are from flat ground. The hypotenuse will always be longer than the distance from the base of the tree.

So, when I'm up in my stand what am I supposed to do with the reading that I get from a rangefinder? Should I reset my all scope settings from an elevated (treestand) position? Do I keep my scope settings as they are, but compensate in some way?

Ninepointer

mikew · Post by **mikew** » Mon Sep 17, 2007 11:23 am

NP,
Most rangefinders will give you the hypotenuse.

There are a couple that I know of that will calculate the horizontal distance, notably the Leupold RX-III and RX-IV (feature called "True Ballistic Range") and the Bushnell Scout 1000 w/ARC and Scout 1500 w/ARC ("Angle Range Compensation").

If you hunt solely from a treestand and don't have a fancy rangefinder with that feature, then I would say yes, not a bad idea to set your scope from an elevated position.

Another option is to know what the difference is between the rangefinder reading and true horizontal distance for a few common ranges at the height you normally hunt.

Hope that helps some.

-Mike

Galgo · Post by **Galgo** » Wed Sep 19, 2007 12:47 pm

Do some hypoteneuse calculations and you are going to probably find it negligible at bow ranges.

F

Michael Stogre · Post by **Michael Stogre** » Wed Sep 19, 2007 1:37 pm

It has been suggested to sight in one inch low at 20 yards on the
horizontal plane. You will then be right on shooting from your tree-stand
due to the gravitational effect.

Michael Stogre · Post by **Michael Stogre** » Wed Sep 19, 2007 1:38 pm

It has been suggested to sight in one inch low at 20 yards on the
horizontal plane. You will then be right on shooting from your tree-stand
due to the gravitational effect.

Rich · Post by **Rich** » Wed Sep 19, 2007 4:22 pm

Ninepointer,

I took these reading from the treestand set up in my backyard. The treestand is 18 feet high. Rangefiner used was the Leupold RX-II in Bow True Ballistic Range (TBR) mode.

The readings are broken down into Line of Sight to target/TBR/Angle of the shot:

10 yards/10 yards/-32 degrees

20/19/-16

30/29/-9

40/39/-7

50/49/-6

I'm not smart enough to do the math to see how accurate the readings are, but the differance is not enough for me to worry about. If you are hunting higher it may come into play more. Now was the RX-II worth the extra 40 bucks, don't really know but it will sure keep me occupied during the down time in the stand.

Rich

tracer · Post by **tracer** » Wed Sep 19, 2007 5:01 pm

Keep it simple brothers, from 20 yards in, it is not going to matter. Aim for the vitals behind the shoulder and as long as the deer is not looking at you, the deer will not jump the string and you will have made a successful shot.

pokynojoe · Post by **pokynojoe** » Wed Sep 19, 2007 5:09 pm

You don't need fancy "ballistic calculators" to figure true horizontal distance. If you know about what the firing angle is, and the distance(as given from your rangefinder) you can quickly and easily calculate the true horizontal distance or gravitational distance. You can also find and copy a simple sniper correction table and tape it to your stock. I think Matthias has a correction table and info that explains firing angles. check it out. This is all basic riflecraft that everyone learned long before rangefinders were ever heard of. Come on people! Use your noggins!

Joe

aerostarp · Post by **aerostarp** » Wed Sep 19, 2007 5:26 pm

Having had some time on my hands I did calculate all the differences in both height (12' to 20' treestand height) and distance (20yds. out to 60 yds.). Basically the difference is greatest the higher you are or the closer the target. However, as Rich shows with his rangefinder it is pretty much moot because we are talking negligible amounts at bow ranges

. Long rifle shots up and down mountains and valleys it makes a big difference. Wonderful site and incredibly informative. Thanks. Wayne

Rich · Post by **Rich** » Thu Sep 20, 2007 7:29 am

Aerostarp,

Do you happen to have your results on a spreadsheet or chart you could post. I think it would be benefial for a lot of us.

Thanks Rich

aerostarp · Post by **aerostarp** » Thu Sep 20, 2007 8:42 am

Do you happen to have your results on a spreadsheet or chart you could post. I think it would be benefial for a lot of us.

Yes Rich - I will post them shortly. Thanks for your interest. Wayne

aerostarp · Post by **aerostarp** » Thu Sep 20, 2007 5:49 pm

Damn: I typed out the entire chart I made up and when I went to review it it was all jumbled together. When I hit the back button it all dissappeared

I will try it again more in a narrative.

(1) A 12' treestand with a Rangefinder value (RV) of 15 yds. will have an actual horizontal range (HR) of 14.4 yds. At 25 (RV) it will be 24.7
(HR). At 35 (RV) it will be 34.8 (HR). At 45 (RV) it will be 44.8 (HR) and at 55 (RV) it will be 54.9 (HR).

(2) A 15' treestand will be 14.1 (HR) at 15 (RV), 24.5 at 25, 34.6 at 35, 44.7 at 45 and 54.8 at 55.

(3) A 18' treestand will be 13.7 at 15, 24.3 at 25, 34.5 at 35 44.6 at 45 and 54.7 at 55.

(4) A 21' treestand will be 13.3 at 15, 24.0 at 25, 34.3 at 35, 44.5 at 45 and 54.6 at 55.

(5) A 30' treestand will be 11.2 at 15, 22.9 at 25, 33.5 at 35, 43.9 at 45 and 54.1 at 55.

As you can see the closer the target or the higher the stand the shorter is the actual horizontal range compared to the Rangefinder value. However, unless the deer is within 15 yards from a 25'+ treestand I am not sure it really matters that much. Wayne

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