Ballistic rangefinder temperature effects on data output bandaid

[MC2FS]

Here’s a question for you I haven’t tried to proof the concept of so I’m posing it to the masses for a sanity check first.

I have noticed that my rangefinder with built in atmospheric sensors reads on average 10-15°F warmer than actual ambient temp when it’s stowed in my bino harness and hiking around in the field. When I zero my rifle I always use the actual ambient temp for that profile taken from a kestrel or other means.

My question is, would I not have to worry as much about my ballistic output being off by .1-.2mil at distance with varying ambient temps if I use the temp from the rangefinder instead as long as it hadn’t been sitting around abnormally ie. in the sun, on a rock, etc.

This makes sense in my head but wanted to see if I’m missing something or if it’s been tried before.

 

[Formidilosus]

Here’s a question for you I haven’t tried to proof the concept of so I’m posing it to the masses for a sanity check first.

I have noticed that my rangefinder with built in atmospheric sensors reads on average 10-15°F warmer than actual ambient temp when it’s stowed in my bino harness and hiking around in the field. When I zero my rifle I always use the actual ambient temp for that profile taken from a kestrel or other means.

My question is, would I not have to worry as much about my ballistic output being off by .1-.2mil at distance with varying ambient temps if I use the temp from the rangefinder instead as long as it hadn’t been sitting around abnormally ie. in the sun, on a rock, etc.

This makes sense in my head but wanted to see if I’m missing something or if it’s been tried before.

No. Your 100 yard zero isn’t affected by different temps. The drop at distance is.

 

[MC2FS]

No. Your 100 yard zero isn’t affected by different temps. The drop at distance is.

That’s not the question I’m asking though.

It’s, if I fudge my temp in the profile setup to go with the rangefinders temp (which is skewed from the actual ambient temp) for my zero conditions, will my drop at distance be more or less correct?

Let’s assume I have the velocity already figured for the powder im using at the differing temps too. In that case say I zero at 10°F ambient temp, my rangefinder reads something like 25°. In the ballistic profile setup, if I enter that I zeroed at 25 instead of 10, would the ballistic output be more accurate at distance for days it’s ~85° and reads 100°? Or a day where it’s 45° and the rangefinder gets a little warm for whatever reason and shows 75?

 

[khart_6882]

Just jumped on a ballistic app. The difference between 50° and 65° with a .243 at 600 yards is .2 inches in drop. Small potatoes dude. Even a 35° temperature swing shows .4 inches at 600 yards

 

[MC2FS]

Just jumped on a ballistic app. The difference between 50° and 65° with a .243 at 600 yards is .2 inches in drop. Small potatoes dude. Even a 35° temperature swing shows .4 inches at 600 yards

Ya, I agree. 800 and in is pretty much a wash. Just thinking longer than that and the scenerios when it does capture a higher than it’s usual temp. Puts it .1mil or more off at 1k.

 

[wpeach1912]

Here’s a question for you I haven’t tried to proof the concept of so I’m posing it to the masses for a sanity check first.

I have noticed that my rangefinder with built in atmospheric sensors reads on average 10-15°F warmer than actual ambient temp when it’s stowed in my bino harness and hiking around in the field. When I zero my rifle I always use the actual ambient temp for that profile taken from a kestrel or other means.

My question is, would I not have to worry as much about my ballistic output being off by .1-.2mil at distance with varying ambient temps if I use the temp from the rangefinder instead as long as it hadn’t been sitting around abnormally ie. in the sun, on a rock, etc.

This makes sense in my head but wanted to see if I’m missing something or if it’s been tried before.

Lock your temp reading and input it manually if you’re looking for a “perfect” solution for a farther shot. You should be locking your kestrel’s temp readings too and only updating when temp changes significantly

 

[Formidilosus]

That’s not the question I’m asking though.

It’s, if I fudge my temp in the profile setup to go with the rangefinders temp (which is skewed from the actual ambient temp) for my zero conditions, will my drop at distance be more or less correct?

Let’s assume I have the velocity already figured for the powder im using at the differing temps too. In that case say I zero at 10°F ambient temp, my rangefinder reads something like 25°. In the ballistic profile setup, if I enter that I zeroed at 25 instead of 10, would the ballistic output be more accurate at distance for days it’s ~85° and reads 100°? Or a day where it’s 45° and the rangefinder gets a little warm for whatever reason and shows 75?

No. The bino reading the environmental conditions it’s currently in, has nothing to do with your zero or the day your zeroed it. If it’s reading 25° F, but it’s really 0° F- it is using that temp to calculate (along with pressure) the data you need. The day you zero has nothing to do with it.

 

[Formidilosus]

Just jumped on a ballistic app. The difference between 50° and 65° with a .243 at 600 yards is .2 inches in drop. Small potatoes dude. Even a 35° temperature swing shows .4 inches at 600 yards

It’s reading more than just temp.

 

[khart_6882]

It’s reading more than just temp.

I’m not a meteorologist, but if it is showing a 15-20 degree false temperature reading, would that also give enough of a false barometric pressure reading to effect a shot?

 

[Formidilosus]

I’m not a meteorologist, but if it is showing a 15-20 degree false temperature reading, would that also give enough of a false barometric pressure reading to effect a shot?

It would depend on how each unit is pulling environmental data.

 

[MC2FS]

I’m not a meteorologist, but if it is showing a 15-20 degree false temperature reading, would that also give enough of a false barometric pressure reading to effect a shot?

Pressure reading has always been very near my other devices. Just the temp varies. Sometimes RH is a little off but that is a relatively small input.

 

[MC2FS]

No. The bino reading the environmental conditions it’s currently in, has nothing to do with your zero or the day your zeroed it. If it’s reading 25° F, but it’s really 0° F- it is using that temp to calculate (along with pressure) the data you need. The day you zero has nothing to do with it.

Now we’re getting somewhere. Why the hell do they have you input your zero conditions then?

 

[SloppyJ]

What this boils down to is the temp stability of your powder and if the input data you have in your solver will be off by 15 degrees? Most of us dont even both with specifying any of the temp/velocity data. I think you'll be fine man.

 

[Formidilosus]

Now we’re getting somewhere. Why the hell do they have you input your zero conditions then?

If you zero beyond 100 yards, you need current conditions.

Which bino?

 

[Formidilosus]

What this boils down to is the temp stability of your powder and if the input data you have in your solver will be off by 15 degrees? Most of us dont even both with specifying any of the temp/velocity data. I think you'll be fine man.

It’s more than that. If you have the bino inside your jacket in say 10° F weather, the bino is reading conditions 60-70°F. It is normal if the bino has been in your jacket for it to give elevation data that is .1 to .3 mil off at 600 yards until it has reached ambient outside conditions.

 

[MC2FS]

If you zero beyond 100 yards, you need current conditions.

Which bino?

Handheld. Razor 4k GB

 

[Formidilosus]

Handheld. Razor 4k GB

It’s for if you zero beyond 100 yard POA/POI.

 

[SloppyJ]

It’s more than that. If you have the bino inside your jacket in say 10° F weather, the bino is reading conditions 60-70°F. It is normal if the bino has been in your jacket for it to give elevation data that is .1 to .3 mil off at 600 yards until it has reached ambient outside conditions.

I was just going off of his numbers in the post.

Still think we are splitting hairs. If ive learned nothing else.... the wind call will be off way more. The 2.16" of elevation potential isn't going to keep me up at night but good to know it could become a possibility.

I get it though, another variable. I want that stuff to just work too.

 

[MC2FS]

It’s for if you zero beyond 100 yard POA/POI.

With all that being said now, your first comment makes a lot more sense.

 

[Formidilosus]

Still think we are splitting hairs. If ive learned nothing else.... the wind call will be off way more. The 2.16" of elevation potential is the least of my problems.

I get it though, another variable. I want that stuff to just work too.

Well…. I missed a very large buck a few years ago due to it with Leica Geovid Pro’s. Granted it was 860 yards IIRC, but it was a .5 mil (15”) error going from a 70°’ish to single digits real temp. Took about 12-15 minutes for it to reach ambient and start reading correct again.

Happens all the time while shooting in cold weather. One of the reasons for this: