How hot can a scope get?????

[jb77]

A friend of mine accidentally left a rifle locked in his truck while he was out of town for a week. The truck was parked in his driveway in the full sun. The temperatures were getting up to about 101-104 here all last week.

I am not sure exactly how hot it gets inside a closed up vehicle on a hot day, but it feels pretty d--- hot.

His question was, is this bad for his scope? I am not sure.

Opinions please.

 

[280man]

That kind of heat is hard on everything I believe I've read that it can get upwards to 140-150 degrees inside a car in the direct sun having said that he should be fine assuming its a quality scope

 

[TresMon]

Regarding the age old story of idots leaving animals and kids in cars in the summer- Ive heard news reports that vehicles can get over 200 degrees in summer heat whilse sitting in full sun.

 

[blacknwhite]

I have always wondered about this myself...So while we are on the subject maybe one of the experts can comment on the extreme cold as well. I have left a scoped rifle in the truck in both conditions and have always wondered if it was doing damage.

 

[Fred Bohl]

Within the range of say -40 to + 180 degrees Fahrenheit most midrange to high quality scopes should be fine. The first area of problems will be with the seals and inert gas,typically Nitrogen or Argon) fill. At high temperatures the internal pressure will rise and may cause out gassing while at low temperatures the internal pressure will drop and may allow outside air to infiltrate,with its water vapor). At more extreme temperatures or on lower quality scopes the seals may fail permanently.

Depending on the particular design, you may also experience a shift in POA because of relative motion of the internal parts due to different rates of thermal expansion and contraction that do not return to their initial positions when the scope returns to normal temperatures.