Figure this one out...I sure haven't

sharpbb14

FNG
Joined
Sep 7, 2016
Messages
30
Location
Powell, Wyoming
Shooting my bow in the heat of the day and sighting it in I got it dialed in perfect. The next day it is shooting significantly low when shooting in the cool morning. This has been an ongoing issue for a couple of months. I have made the following changes
1) replaced my Shaffer rest with a QAD hdx as I felt the Shaffer was wearing out.
2) increased arrow FOC from 8.9 to 11.3% to gain improved arrow flight, required going from 100 to 125grain heads
3) got bow retimed and retuned. Shooting perfect pinwheels now. Did require a couple cable twists
4) got a smaller peep to reduce floating the pin. Definitely feel very consistent with my shot.

My groups are very good, but there is an elevation difference at all ranges.

Here is my final guess: I shoot over lush grass. The owners of the property water very heavily due to heat and dry climate. As the sun heats up, evaporation increases and rises, making my arrows "float" a bit more. When it cools down, and there are reduced heat waves/evaporation, the arrows fly more true.
My solution: I hunt in dry climate, so I'm gonna sight my bow in during the morning coolness and leave it there, knowing it will be high while Target practice in the middle of the day.
WHAT DO Y'ALL THINK???
 
OP
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sharpbb14

FNG
Joined
Sep 7, 2016
Messages
30
Location
Powell, Wyoming
All distance. 20 yards it is a 1.5-2 inch difference. At 70 yards 8-9 inch difference. At 100 yards 12-14 difference
 

SWOHTR

WKR
Joined
Aug 1, 2016
Messages
1,439
Location
Briney foam
Are you sure your anchor doesn’t change? I’ve had similar problems and traced it back to my anchor. Fatigue, sweaty hands, chin all factor in. What kind of release are you using? If it’s a wrist strap, is it always at the same point on your wrist and hand?


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Joined
Jun 30, 2015
Messages
355
Location
Ohio
Is either shooting time done in low light? I find that if you dont have a solid anchor you can lose the crisp outline of the peep in low light and end up shooting high/low depending on anchor. I cant see a temp difference causing a 2" change at 20 yards personally.
 
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sharpbb14

FNG
Joined
Sep 7, 2016
Messages
30
Location
Powell, Wyoming
Swohtr- I feel as if my anchor point is pretty consistent. I really don't have much evidence that would suggest I utilized a different anchor last night as opposed to this morning. I use the spot Hogg wise guy. I will make a conscious effort to pay attention to this aspect. Thanks
 
Joined
Aug 9, 2017
Messages
469
Location
Southeast Texas
Have you checked all of your serving to make sure your strong isn’t settling weird when it warms up? An inch plus at 20 yards is a bit much to think that atmospheric pressure causes it. I could see an inch at 50, but at 20 it seems more likely for it to be a mechanical issue
 
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sharpbb14

FNG
Joined
Sep 7, 2016
Messages
30
Location
Powell, Wyoming
Wapitibob- the techs that tuned and times the bow said the cables and string were good to go. So I hope that isn't the issue. I plan on keeping them waxed and well taken care of. Thanks
 

92xj

WKR
Joined
Apr 22, 2016
Messages
1,234
Location
E.Wa
Shoot at the same times in the day as on the grass in the driveway and see if you get the same 2" difference at 20 yards. I'd guess you would and would eliminate the irrigation of lush grass thoughts.
 
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sharpbb14

FNG
Joined
Sep 7, 2016
Messages
30
Location
Powell, Wyoming
Mathews8pt- the sun was shining during both times, both there was at least a 25 degrees temperature difference. I have heard and been told the lighting can mess with vision through the peep so I have been ultra-aware of my alignment. Thanks sir
 
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sharpbb14

FNG
Joined
Sep 7, 2016
Messages
30
Location
Powell, Wyoming
Gerard- servings all look good. The recent, and reliable bow techs that recently checked out the bow said it checked out good. Thanks
 
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sharpbb14

FNG
Joined
Sep 7, 2016
Messages
30
Location
Powell, Wyoming
Thanks everyone for the help. All good feed back. I'm sure my theory isn't what it is and it is something in my form. I will keep at it. God bless
 

bwlacy

WKR
Joined
Feb 11, 2015
Messages
424
Location
West Michigan
I would go with the string and cables also. Used to be quite common 20 years ago with poor string material. I would tune my bow here in Michigan in February and head to Georgia or Florida for 3D shoots and everything was way different in the heat. Started bringing a press with me and fixing it at the shoots.

Today there are much better string options and that normally isn't a big deal until they are worn out.
 
Joined
May 10, 2015
Messages
2,051
Location
Timberline
wapitibob is correct. Heat of the day, your string will stretch, hence marking your cams to see if they change position from the string stretching.
 
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