I am so confused.

[oldsparky]

I have a Huntsman Regal XL in .177, shooting JSB Exact 10.34 pellets. I have my crosshairs sighted in @ 35 yards. I have had a drawing of my reticle and thought I knew my yardage marks well. I recently moved my scope back a half an inch by sliding the rings on the rail and tightening back up. I only had time to check my 0 @ 35 yards and it was good. Today I went out shooting off my bench its breezy enough to see leaves moving and tall weed moving but not that big a deal I thought. Anyway where I am confused was my yardage marks seem really off. I usually use a mark that is 3 MOA down @ 50 today I was using 1 MOA down @ 50 seeming like my rifle was shooting very flat. The ambient is about 90F but can a 20 degree shift make that much difference? Or was there wind that I am not reading right. I still shout a half inch group at 50 yards so the wind wasn’t that erratic. My air pressure is the same, checked by two gauges. What are your thoughts?

 

[shutik]

Wind from 6 O'Clock will raise POI. Warmer temperatures will raise POI. Also scope will shift POI with temperature change.

Just shoot at different conditions and learn how much different weather impacts your equipment.

 

[Eddy1840]

"shutik"Wind from 6 O'Clock will raise POI. Warmer temperatures will raise POI. Also scope will shift POI with temperature change.
Just shoot at different conditions and learn how much different weather impacts your equipment.

Can you explain us why the temperature affects the scope??

 

[cally88]

As i understand it the temperature does not directly impact the scope specifically, it is more of a poi change due to the change in air density.

 

[ohio_hunter]

I don't have a huntsman rifle but I have other rifles and they shoot the same at 17 degrees as they do 77 degrees.

 

[eric._mills1]

Do you have shimmed rings? Did you torque your rings exactly the same as before? Was your fill the same as previous fills?
The reason I ask is because if you have shimmed rings moving the scope rearward could mechanically change elevation if the powder coating on the scope tube was thicker near that section of the scope tube, or one of your shims could have shifted ever so slightly.
Also if you torqued your rings differently that can change point of impact as well. And it is also possible that your fill might have been off a bit and you discovered ( by accident) a new sweet spot in your power curve. All of this is pure speculation.

 

[shutik]

"Eddy1840"

"shutik"Wind from 6 O'Clock will raise POI. Warmer temperatures will raise POI. Also scope will shift POI with temperature change.
Just shoot at different conditions and learn how much different weather impacts your equipment.

Can you explain us why the temperature affects the scope??

Scope is made out of metal parts, and as temperature increases metal heats up and expands. Most of scopes will shift parallax distance when it is hotter.

 

[Guest]

While the scope moving with temperatures may be an influence it's likely this. Your scopes line of sight is intersecting your pellets trajectory at different places. This will cause your holdovers or clicks to change. 

 

[oldsparky]

"shutik"

"Eddy1840"

"shutik"Wind from 6 O'Clock will raise POI. Warmer temperatures will raise POI. Also scope will shift POI with temperature change.
Just shoot at different conditions and learn how much different weather impacts your equipment.

Can you explain us why the temperature affects the scope??

Scope is made out of metal parts, and as temperature increases metal heats up and expands. Most of scopes will shift parallax distance when it is hotter.

Air pressure is verified the same in the rifle. what I started doing awhile back to be sure my pressure is constant is after 30 shots I refill to 200 bar. I didn't move the scope in the rings. I moved the rings rearward 1/2" on the rail.

thanks.

 

[oldsparky]

"John_in_Ma"While the scope moving with temperatures may be an influence it's likely this. Your scopes line of sight is intersecting your pellets trajectory at different places. This will cause your holdovers or clicks to change.

Can you explain this to me. I am not following? Also my -0- is didn't change 15 - 35 impact is still my cross hairs. But what is different is my impact at 40 - 55 yards and my 10 yard. there is less drop. Its like I am shooting lighter pellets or my velocity is faster. My holdovers changed a little over a MOA. My chronograph is down so I can't check. the velocity thats probably what I need to verify first.. Just thought I would post this as a question.

thanks, Jim

 

[oldsparky]

Well, I guess I’m a idiot. I shot about a hundred rounds yesterday. It was 97 degrees out and the wind was still. Guess what my holdover marks were right on. I guess there was more wind out, when I had the problem than I thought. I guess I need to put out some wind indicators throughout my range to see wind at different yardages. Thanks for all the help, Jim