Rifle Scopes Can you leave a rifle scope in a hot car?

[Long Range]

I am sometimes forced to leave a rifle scope in a hot car. It gets pretty hot inside the car especially on 85+ degree days.

My searches came up with nothing so I am wondering if it is a bad idea to leave a rifle scope in a hot car.

 

[PDXGS]

Yes-if it's a better quality scope. Some scope manufacturers use adhesives and lubricants that start to soften, liquefy or vaporize at temps under 100deg F. It's not as hot in your car as say Iraq or Afghanistan or Phoenix in 120 deg F heat...where trunk temps can exceed 180 deg F.
Keep it out of direct sunlight if you can- if you can't, cover it with a shemagh or a towel.

 

[VJJPunisher]

if it cant it shouldnt have been boughten, confucious once say

 

[kl3309]

Serious answer: Really high temps will have whatever gas was used to purge your scope expand and increasing pressure inside of your scope causing that gas to push out past the seals.

Preferred answer: I leave my childrens in a hot car all the time, they ain't complainin'.

 

[FS1]

Serious answer: Really high temps will have whatever gas was used to purge your scope expand and increasing pressure inside of your scope causing that gas to push out past the seals.

Preferred answer: I leave my childrens in a hot car all the time, they ain't complainin'.

That is why they use nitrogen it is not as pressure/temperature sensitive as other gases. The same reason race cars use it in their tires.

 

[kl3309]

That is why they use nitrogen it is not as pressure/temperature sensitive as other gases. The same reason race cars use it in their tires.

They use nitrogen in optics because it's (relatively) inert (so won't react with other materials) and it doesn't carry moisture (precluding internal fogging). And that hydrophobic quality is applied to racing tires because, at racing temps, moisture in regular air will boil out causing a spike in tire pressure and altering the car's (handling) balance.

Note that some manufacturers are using argon in lieu of nitrogen because argon's comparatively larger molecules do not diffuse past the seals as readily as nitrogen's making the purge longer-lasting.

 

[Nortex]

Leave mine all the time in our north texas 100+ temp summer days with no issues.

 

[FS1]

They use nitrogen in optics because it's (relatively) inert (so won't react with other materials) and it doesn't carry moisture (precluding internal fogging). And that hydrophobic quality is applied to racing tires because, at racing temps, moisture in regular air will boil out causing a spike in tire pressure and altering the car's (handling) balance.

Note that some manufacturers are using argon in lieu of nitrogen because argon's comparatively larger molecules do not diffuse past the seals as readily as nitrogen's making the purge longer-lasting.

Of course moisture is the main enemy here and both nitrogen and argon are dry. And both are inert to prevent reaction.

But lets go the other way, what if you fill an optic with vapor at 70 degrees and now go to the arctic at -40. That optic is going to be in a negative pressure, if a very P/T sensitive gas is used. Negative pressure means moisture and air can be sucked into the optic. So you want to use a gas that is not very P/T sensitive.

I have not heard of the use of argon because the molecule is bigger. Though it does make logical sense.

 

[Long Range]

I'm confused here, so will the nitrogen inside my scope push out passed the seals?

If it does what will happen?

I own a vortex viper scope so I assume I can get it warrantied if this happens. But will I notice something is wrong with the scope or will my accuracy or clarity just get worse?

 

[FS1]

I'm confused here, so will the nitrogen inside my scope push out passed the seals?

If it does what will happen?

I own a vortex viper scope so I assume I can get it warrantied if this happens. But will I notice something is wrong with the scope or will my accuracy or clarity just get worse?

This is only a guess on my part but I would think moisture (condensation) inside the scope would be the first indication.

 

[g2gjoe]

Hmmmm, i've got some old Simmons scope's in a box somewhere in the garage.
Does anybody care to see a scope in an oven review?

 

[CMH]

Hmmmm, i've got some old Simmons scope's in a box somewhere in the garage.

Plant one in the garden. Water and fertilize faithfully. Let us know if it grows into a real scope.

 

[g2gjoe]

Plant one in the garden. Water and fertilize faithfully. Let us know if it grows into a real scope.

Do you mean like a super sniper scope or Shepherd?lol
Then I would be totally "Operator as fuck"
Touché CMH, glad to see I'm not the only smart ass around here.

 

[Long Range]

It is hard to believe that the scopes can't take the heat of a car. My gun out in the sun is so hot to the touch, it burns my face when looking through the scope. I am sure they figure that the scope laying out in the sun is going to get really hot.

Also, it would be more of a known issue if scopes broke because of heat I think.

 

[M40_A1]

Serious answer: Really high temps will have whatever gas was used to purge your scope expand and increasing pressure inside of your scope causing that gas to push out past the seals.

Seriously??

If the pressure in the scope is ambient at 14.7 psi at sea level when assembled in a 68-degree F assembly room, then raising that temperature to 150-degrees F would raise the internal pressure to 16.98 psi, a mere 2.28 psi. The seals cannot withstand that? Then how are we able to take scopes from sea level to 5000 feet with no problems? Ambient pressure drops (or the pressure inside the scope raises in relation) about 2.47 psi when going from sea level to 5000 ft., which is more than the 2.28 psi difference created by raising the temperature to 150 F. If the scope's seals leak at under 3 psi, may I suggest a purchasing from a different manufacturer?

 

[Jared91]

Seriously??

If the pressure in the scope is ambient at 14.7 psi at sea level when assembled in a 68-degree F assembly room, then raising that temperature to 150-degrees F would raise the internal pressure to 16.98 psi, a mere 2.28 psi. The seals cannot withstand that? Then how are we able to take scopes from sea level to 5000 feet with no problems? Ambient pressure drops (or the pressure inside the scope raises in relation) about 2.47 psi when going from sea level to 5000 ft., which is more than the 2.28 psi difference created by raising the temperature to 150 F. If the scope's seals leak at under 3 psi, may I suggest a purchasing from a different manufacturer?

This

sent from Jennifer Lawrence's bedroom

 

[pinklbd]

Seriously??

If the pressure in the scope is ambient at 14.7 psi at sea level when assembled in a 68-degree F assembly room, then raising that temperature to 150-degrees F would raise the internal pressure to 16.98 psi, a mere 2.28 psi. The seals cannot withstand that? Then how are we able to take scopes from sea level to 5000 feet with no problems? Ambient pressure drops (or the pressure inside the scope raises in relation) about 2.47 psi when going from sea level to 5000 ft., which is more than the 2.28 psi difference created by raising the temperature to 150 F. If the scope's seals leak at under 3 psi, may I suggest a purchasing from a different manufacturer?

All bets are off if u have to put it on a plane.

 

[CMH]

All bets are off if u have to put it on a plane.

Like when you ship it Priority Mail or by any expedited method through UPS or Fed Ex?

 

[sib1948]

Here in Arizona I've had not issues and considered problems from the heat after the testing and service environments they have endured.

 

[E. Bryant]

But lets go the other way, what if you fill an optic with vapor at 70 degrees and now go to the arctic at -40. That optic is going to be in a negative pressure, if a very P/T sensitive gas is used. Negative pressure means moisture and air can be sucked into the optic. So you want to use a gas that is not very P/T sensitive.

All dry gases respond the same to changes in temperature as described by our good ol' friend Ideal Gas Law. You can fill a scope with hydrogen or radon (I wouldn't recommend either), and it won't affect the manner in which pressure changes with temperature. This shit used to be taught in school, but that ain't what it used to be.

As the use of argon pertains to scopes, the molecule is indeed larger and thus leaks more slowly, but I suspect that the primary benefit is that of marketing (argon being substantially less common - although it's the third-most common gas in our atmosphere - and thus seems more exotic to the average end user). For what high-end scopes cost, they should be using krypton if for no other reason than it sounds fuckin' awesome.

Any scope that incurs a leak or other failure (such as migration of lubricant) by virtue of being stored in a hot car has absolutely no place on a practical rifle.

 

[majohnson2]

If you crack the windows 1/2" on each side, or with a sunroof most have a function to where you can tilt the back edge. In doing so will reduce the in car temperature by at least 15 to 20 degrees. It will also aides in saving your auto interior.

 

[FS1]

All dry gases respond the same to changes in temperature as described by our good ol' friend Ideal Gas Law. You can fill a scope with hydrogen or radon (I wouldn't recommend either), and it won't affect the manner in which pressure changes with temperature. This shit used to be taught in school, but that ain't what it used to be.

As the use of argon pertains to scopes, the molecule is indeed larger and thus leaks more slowly, but I suspect that the primary benefit is that of marketing (argon being substantially less common - although it's the third-most common gas in our atmosphere - and thus seems more exotic to the average end user). For what high-end scopes cost, they should be using krypton if for no other reason than it sounds fuckin' awesome.

Any scope that incurs a leak or other failure (such as migration of lubricant) by virtue of being stored in a hot car has absolutely no place on a practical rifle.

PV=nRT The ideal gas law is only an approximation of how a gas will react under certain conditions, because there are no ideal gases. Gases in the real world don’t always obey.

I agree that all dry gases will behave in the same way. When enclosed in a fixed volume pressure will increase as temperature increases. But all gases will not experience the same amount of increased pressure.

If I filled liter bottles of argon, oxygen, nitrogen, helium, etc. at atmospheric pressure, then capped them put them in the sun with pressure gauges and observed. If I understood your point correctly they would all increase the same in pressure. I don’t think they would all increase the same.

If this thinking is flawed please help me to understand why I am wrong.

I really think the main point has been made here. If your optic is not built well enough to remain sealed under severe conditions buy better ones. And even good ones wear out over time.

 

[damoncali]

PV=nRT The ideal gas law is only an approximation of how a gas will react under certain conditions, because there are no ideal gases. Gases in the real world don’t always obey.

I agree that all dry gases will behave in the same way. When enclosed in a fixed volume pressure will increase as temperature increases. But all gases will not experience the same amount of increased pressure.

If I filled liter bottles of argon, oxygen, nitrogen, helium, etc. at atmospheric pressure, then capped them put them in the sun with pressure gauges and observed. If I understood your point correctly they would all increase the same in pressure. I don’t think they would all increase the same.

If this thinking is flawed please help me to understand why I am wrong.

I really think the main point has been made here. If your optic is not built well enough to remain sealed under severe conditions buy better ones. And even good ones wear out over time.

You're right, but the difference isn't all that much.

 

[Nysios]

Did this for years with some of the cheaper Leupolds, if a hot car makes it leak gas throw it in the trash. You should be fine

 

[Martin Taylor]

For what high-end scopes cost, they should be using krypton if for no other reason than it sounds fuckin' awesome.

Leupold does this.

 

[E. Bryant]

PV=nRT The ideal gas law is only an approximation of how a gas will react under certain conditions, because there are no ideal gases. Gases in the real world don’t always obey.

Deviation from the Ideal Gas Law happens primarily at very low temperatures (those near absolute zero) or extremely high pressures - neither of which are a factor in this discussion.

I agree that all dry gases will behave in the same way. When enclosed in a fixed volume pressure will increase as temperature increases. But all gases will not experience the same amount of increased pressure.

Under the conditions that we are discussing, the pressure vs. temperature increase will be the same for all practical purposes. I don't think that I own any equipment capable of measuring the difference, and that includes some sensors with a resolution of approximately 0.01 kPa.

 

[UNCIVILIZED]

You can always purchase a light colored car cover for your vehicle. Particularly if it has a dark colored interior. And... the cover (to some degree) gives you the perk of keeping interesting looking items inside of the vehicle out of sight.
Still, it'd be interesting for someone to do a poll about this, by contacting the engineers (sic) @ a number of optics companies.

 

[Roentgun]

Deviation from the Ideal Gas Law happens primarily at very low temperatures (those near absolute zero) or extremely high pressures - neither of which are a factor in this discussion.

This is how I remember both from physics and from SCUBA classes.

 

[shovelstrokeed]

You're right, but the difference isn't all that much.

There is a non-ideality factor for all gases but it is only relevant to temperatures down near the boiling point of the gas. 73K for N2, 83K for AR. Doesn't apply here. The gases will, assuming no leaks or permeability of the bottle, all behave the same. Remember also that t, the temperature, must be in Kelvin units.

 

[Mike]

Did this thread really happen??

 

[Nysios]

Did this thread really happen??

We get bored some time Mike...

 

[VJJPunisher]

smeagol once say "my butthole stores my precious at a room temperature", maybe try that next time?

 

[M40_A1]

It was a reasonable question. I think the answer could be summed up thusly......high temperatures certainly don't do your scope any good. Avoid it as much as possible and your seals will thank you for it for a long time to come.

 

[delixe]

smeagol once say "my butthole stores my precious at a room temperature", maybe try that next time?

More sage advice from VJJ.