Tndeer Logo

Page 1 of 2 12>
Topic Options
#2898020 - 08/06/12 02:56 PM Setting CrossBow Scope Questions
fairchaser
8 Point


Registered: 09/13/11
Posts: 1343
Loc: TN, USA

Offline
I have an Excalibur Crossbow that shoots 330 FPS and have the scope adjusted so that from the ground, it shoots accurately for the multi-lines at 10-50 yards. My question is could the speed adjustment on the scope be adjusted to accurately compensate for a tree stand angle? The X bow should shoot high using the yardage measured from an elevated position, so I was thinking I could adjust the speed on the scope a little faster to compensate for this. Anyone have any experience here?
_________________________
"I always wanted to do something that was unequivocal" Charles Morris played by Anthony Hopkins in the movie the Edge.

Top
#2898066 - 08/06/12 03:53 PM Re: Setting CrossBow Scope Questions [Re: fairchaser]
Rubberduck270
10 Point


Registered: 11/01/10
Posts: 2983
Loc: Lawrence Co.

Offline
It will shoot the same as long as you go by the horizontal distance rather than the line of sight. Meaning, rather than estimating how far the deer is from your eyeball (line of sight) estimate his distance from the bottom of your stand.

That being said, the effect that the height of your stand has on the arrow is negligible. I know alot of rangefinder companies have made a ton off of ARC (angle range compensation or something similar) but it's really not worth it.

Say you are shooting on a 45 degree angle (i.e. You're 15 ft up a tree and the deer is 15 ft from the base of your tree). From your eyeball to the deer is ~21 ft. Not sure about your crossbow but mine is deadnuts with the first mark out to 25 yards, therefore you're gonna use the first crosshair from 0-25 yards. The 6ft difference isn't worth worrying about.

Moving out a little farther and say the deer is at 20 yards and you are still 15 ft up the tree. From your eyeball to the deer is 20.6 yrds, so you're still using your first crosshair.

Jump way on out to 50 yrds. with you still 15 ft up the tree. Line of sight distance is 50.25 yrds, so you're still using your 50 yrd crosshair.

Worrying about the difference your height makes isn't really worth your time. If you have it dialed in from the ground you won't have anything to worry about come opening morning when he steps out within ~50yrds.
_________________________
Smokeless Muzzleloading: It ain't your Grampa's flintlock

Top
#2898288 - 08/06/12 08:10 PM Re: Setting CrossBow Scope Questions [Re: Rubberduck270]
fairchaser
8 Point


Registered: 09/13/11
Posts: 1343
Loc: TN, USA

Offline
Thanks Rubberduck. Do you have the formula for the calculation? I am a bit surprised that the difference is so slight once you get out farther but I was never that good with geometry.
_________________________
"I always wanted to do something that was unequivocal" Charles Morris played by Anthony Hopkins in the movie the Edge.

Top
#2898758 - 08/07/12 08:00 AM Re: Setting CrossBow Scope Questions [Re: fairchaser]
Rubberduck270
10 Point


Registered: 11/01/10
Posts: 2983
Loc: Lawrence Co.

Offline
 Originally Posted By: fairchaser
Do you have the formula for the calculation? I am a bit surprised that the difference is so slight once you get out farther but I was never that good with geometry.


It's actually trigonometry rather than geometry.

You use the Pythagorean Theorem. Its the Standard formula for calculating the third side of a right triangle. Where A=Stand Height, B=Horizontal Distance to Target and C=Line of Sight Distance, C=sqrt(A*A + B*B). Or you can use this calculator and find the value of C http://ncalculators.com/number-conversion/pythagoras-theorem.htm/.
_________________________
Smokeless Muzzleloading: It ain't your Grampa's flintlock

Top
#2899040 - 08/07/12 01:04 PM Re: Setting CrossBow Scope Questions [Re: Rubberduck270]
fairchaser
8 Point


Registered: 09/13/11
Posts: 1343
Loc: TN, USA

Offline
 Originally Posted By: Rubberduck270
 Originally Posted By: fairchaser
Do you have the formula for the calculation? I am a bit surprised that the difference is so slight once you get out farther but I was never that good with geometry.


It's actually trigonometry rather than geometry.

You use the Pythagorean Theorem. Its the Standard formula for calculating the third side of a right triangle. Where A=Stand Height, B=Horizontal Distance to Target and C=Line of Sight Distance, C=sqrt(A*A + B*B). Or you can use this calculator and find the value of C http://ncalculators.com/number-conversion/pythagoras-theorem.htm/.



Thanks, that is probably more math than I want to tackle. You ever see a monkey solve a math problem? I will take your word for it RubberDuck. \:D
_________________________
"I always wanted to do something that was unequivocal" Charles Morris played by Anthony Hopkins in the movie the Edge.

Top
#2899094 - 08/07/12 01:41 PM Re: Setting CrossBow Scope Questions [Re: fairchaser]
BlackBelt
10 Point


Registered: 08/09/08
Posts: 3293
Loc: SouthWest TN

content Online
Math makes my head hurt.
Top
#2899220 - 08/07/12 03:46 PM Re: Setting CrossBow Scope Questions [Re: BlackBelt]
Rubberduck270
10 Point


Registered: 11/01/10
Posts: 2983
Loc: Lawrence Co.

Offline
 Originally Posted By: BlackBelt
Math makes my head hurt.


I like it. I also enjoy algebra, trigonometry, statistics, calculus and differential equations. Heck I even enjoy a little mathematics history from time to time.
_________________________
Smokeless Muzzleloading: It ain't your Grampa's flintlock

Top
#2921834 - 08/27/12 09:18 AM Re: Setting CrossBow Scope Questions [Re: Rubberduck270]
holstonangler
6 Point


Registered: 02/25/06
Posts: 970
Loc: Johnson City

Offline
Its more gravity affecting the arrow drop than the actual distance, shooting at downward angles has less gravitational effect on the arrow than shooting horizonally. Thats why there's a difference when shooting high out a treestand as opposed to shooting at ground level.

Edited by holstonangler (08/27/12 09:19 AM)

Top
#2921936 - 08/27/12 10:28 AM Re: Setting CrossBow Scope Questions [Re: holstonangler]
Rubberduck270
10 Point


Registered: 11/01/10
Posts: 2983
Loc: Lawrence Co.

Offline
Gravity affects the arrow the same. No matter if you are shooting horizontally or vertically. The affect of gravity is the same.
_________________________
Smokeless Muzzleloading: It ain't your Grampa's flintlock

Top
#2922093 - 08/27/12 12:59 PM Re: Setting CrossBow Scope Questions [Re: Rubberduck270]
fairchaser
8 Point


Registered: 09/13/11
Posts: 1343
Loc: TN, USA

Offline
 Originally Posted By: Rubberduck270
Gravity affects the arrow the same. No matter if you are shooting horizontally or vertically. The affect of gravity is the same.


Hey Rubberduck:
If you drop an arrow at the same height at the same time that you shoot an arrow will they hit the ground at the same time just like a bullet?
_________________________
"I always wanted to do something that was unequivocal" Charles Morris played by Anthony Hopkins in the movie the Edge.

Top
Page 1 of 2 12>


Moderator:  RUGER, Bobby G, Unicam, CBU93, stretch, Kimber45, Mrs.Unicam, Crappie Luck 
Hop to:
Top Posters
4106479
RUGER
88258
Deer Assassin
65979
BSK
61913
Crappie Luck
51392
spitndrum
Newest Members
bmobrady3, bmo3, chrislee, Patriot123, DT33
13565 Registered Users
Who's Online
56 registered (The_Utility_Dude, MUP, HOOK, bigasports, tap.emtp, TRIGGER, 3 invisible) and 106 anonymous users online.
Forum Stats
13565 Members
43 Forums
99543 Topics
1171125 Posts

Max Online: 788 @ 11/11/13 08:06 PM
Moon Phase
CURRENT MOON
November
Su M Tu W Th F Sa
1
2 3 4 5 6 7 8
9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
30
Forum Donations
The TnDeer.Com Deer Talk Forum is for Tennessee Deer Hunters by Tennessee Deer Hunters. If you enjoy using our Talk Forum and would like to contribute to help in it's up-keep. Just submit your contribution by clicking on the DONATE button below and paying with PayPal or a major credit card. Any amount is much appreciated. Thanks for your support!

TN Burn Safe

Generated in 0.043 seconds in which 0 seconds were spent on a total of 15 queries. Zlib compression enabled.