heat coming from the ground.

M

mr. nobody

Guest
you guys may have covered this in the wind and hot air thread. incase you did i'm sorry there was to much other stuff for me to read to remember, but here is what i was wondering.

in the summer as the day gets hotter does the heat coming up from the ground affect the bullet on it's path to the target? when me and some friends were practicing a few weeks ago we got to noticing something strange was going on. the wind would die down real low and the bullet would still do crazy things. it was good and warm and you could see mirrage in the scope. i know how to read mirrage. long range shooting with centerfires taught me that. these rimfires are a beast all thier own. does the heat raising from the ground have a big affect or not? i'm sure there are other beginners who want to know as well.
 
mr. nobody said:
you guys may have covered this in the wind and hot air thread. incase you did i'm sorry there was to much other stuff for me to read to remember, but here is what i was wondering.

in the summer as the day gets hotter does the heat coming up from the ground affect the bullet on it's path to the target? when me and some friends were practicing a few weeks ago we got to noticing something strange was going on. the wind would die down real low and the bullet would still do crazy things. it was good and warm and you could see mirrage in the scope. i know how to read mirrage. long range shooting with centerfires taught me that. these rimfires are a beast all thier own. does the heat raising from the ground have a big affect or not? i'm sure there are other beginners who want to know as well.
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The mirage of itself has no effect on the bullets flight but it sure does mess with your vision. Mirage can be used to read wind conditions but you will never see straight through it. Like you ain't holdin' where you think you're holdin'. :eek:

D R
 
like i said in the first post. i know how to read the mirrage. i know the military given values for the way it moves. been doing that all my life(my father taught me that at a early age). what i want to know is as the ground warms up as the day goes by does the heat coming up from the ground cause the bullets flight path to change any at all? like you start out at say 70 degrees ground tempature. as the day goes on the ground gets hotter say up to over 90 degrees. the heat will rise as it always does. how much does this affect the bullet in it's flight to the target? has anybody checked this out? i'm just wondering about it. heck everything else affects it. heat, tempature, humidity and wind. why would the heat coming up off the ground not affect it?
 
mr. nobody said:
like i said in the first post. i know how to read the mirrage. i know the military given values for the way it moves. been doing that all my life(my father taught me that at a early age). what i want to know is as the ground warms up as the day goes by does the heat coming up from the ground cause the bullets flight path to change any at all? like you start out at say 70 degrees ground tempature. as the day goes on the ground gets hotter say up to over 90 degrees. the heat will rise as it always does. how much does this affect the bullet in it's flight to the target? has anybody checked this out? i'm just wondering about it. heck everything else affects it. heat, tempature, humidity and wind. why would the heat coming up off the ground not affect it?
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OK if you want to split hairs, I suppose the rising air could have the same value as cross wind. How fast do you think that air is rising? The temp. change will effect ammo as well and light changes as the earth turns will effect the way you are seeing the target. We can also throw in a little scope induced stress just to muddy the water. :D I envy you having the ability to read mirage. I've seen it running right to left or versa-viesa and at the same time streaming off both sides of the target going in opposite directions. :confused: Times running out where are you going to hold? :eek: And are you holding where you think you are?

D R
 
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i've seen mirrage do alot of crazy stuff before. when i was playing with the 50bmg i had i got to shooting things way out past 1000 yards. in cases like that the mirrage can be very unforegiving!!! with scopes like we use at 36 power it gets real bad.

i never gave any mind to about how fast hot air would rise off the hot ground. it wold be great if we had a way of measuring it. it has to affect the bullet some how. how i don't know. that is why i asked on here. there has to be many people who wondered the samething and maybe some might have a answer that we could use. i don't know. but i just had to ask.
 
Hi Mr. Nobody,

I'll give this one a shot... The short answer to "does heat rising from the ground affect the bullet's path?" The short answer is yes. D.R. hit the nail on the head. I don't think mirage in and of itself will move the bullet but your perception of where the target actually is is the thing. If you start shooting in the morning and things heat up as you go along the bullet will encounter rising thermals of air witch you may perceive as mirage. Watch out for those 12 o'clock rises.

I don't pay much attention to mirage at 50 yards. Reading the "breeze" by reading the mirage is not my cup of tea. When mirage is heavy I do what I call "cost averaging". I wait 'till the target stops "moving" and becomes clear. Then shoot, of course all the while watching the flags, especially the flutter of the tails. I've seen mirage so bad, as I'm sure you have, that the target browns out, almost disappearing. When this happens I just wait for a little air movement to clear things a bit. Letting the target settle down. If your down to 5 seconds on the clock...good luck!

By-the-way, while shooting on a nice warm sunny day and some clouds come by, watch out.

I know what I said above is somewhat contradictory, I had a hard time articulating what I wanted to say. I'm sure someone will come along that has a different opinion and can say it better.

Al
 
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Shooting at night, after a warm summer day, with part of the range covered by grass and part by bare dirt, those shooting over grass will have more fun than those shooting over dirt who will see there bullets do strange things even though the tails of there flags are still. I think its rising heat from the ground into cooler air. But can you have mirage at night?
 
If in fact it is moving, measure it with your handheld speedo. I think you need some of James Pappas windflags that show vertical wind.
Butch
 
Thermals

Our range in located on the top of a ridge. There are large buried boulders or rock formations in several locations. After a hot summer sunny day, the heat thermals are an experience. At our night shoots, when the wind dies to nothing, and the wind flag looks at you like your stupid for even bothering to put them out, you get some real strange behavior from the finest of ammo and the absolute best rifles in the world. Although you can not see these thermals, the do cause havoc with the perceived flight of the bullet. We have found, that even though the flags will not show any movement, by placing the lightest tails possible on the flags, you will sometimes see the thermal reaction. Of course, it's just after you have touched one off. and the #@&*%# begins.
 
Thermals and "sink"

Besides the rising air of the thermal you also have a down draft just outside of the thermal feeding the updraft. On top of that the thermal will be rotating so the wind will change directions as it goes by. Radio control sailplane pilots spend their time trying to find the "lift" at the core of the thermal and avoid the "sink" just out side of the thermal. On a nice warm day try a kids bubble machine, you'll wonder how you ever hit center.

Dennis
 
Too much information

Don't have a clue regarding the initial question but hey, when did I ever let that stand in the way.

It really doesn't matter what the condition is doing to your bullet!

There are 3 basic conditions. One that will support a good target, one that won't, and one that would support a good target but much too dangerous. An example of the latter is a significant crosswind such that if you read it right you get an X - otherwise you get a -3.

Let your rifle lead the way. If it tells you not to shoot a condition, or more importantly to quit shooting a condition, please believe it....or not....your choice.
 
Rich In Kansas said:
But can you have mirage at night?
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Could be all in the name.

Back when I shot 3P, we had fun at our local enclosed but open roofed range shooting nights during a couple of weeks in late autumn. Due to some quirk of hydraulics or whatever, we'd end up with one layer of air of lying on top of another layer of a different temperature and at around 8:00 PM that margin would coincide with the shooters to targets line. If you were shooting during that time, the shot's elevation would be anywhere from 8 ring up to 9 ring down depending on how the margin between the two was "floating".

If your spotting scope was nice & clean & you adjusted it carefully, you could usually see this looking somewhat like the waterline in an aquarium.
 
mr. nobody said:
like i said in the first post. i know how to read the mirrage. i know the military given values for the way it moves. been doing that all my life(my father taught me that at a early age). what i want to know is as the ground warms up as the day goes by does the heat coming up from the ground cause the bullets flight path to change any at all? like you start out at say 70 degrees ground tempature. as the day goes on the ground gets hotter say up to over 90 degrees. the heat will rise as it always does. how much does this affect the bullet in it's flight to the target? has anybody checked this out? i'm just wondering about it. heck everything else affects it. heat, tempature, humidity and wind. why would the heat coming up off the ground not affect it?
Click to expand...

You can, with regularity, get caught and end up talking to yourself either early in the day, as the ground warms up or at dusk, as the ground cools. In that first 3-5 feet off the ground, you may have several layers of different temperature air between you and the paper and it can get very frustrating. Unless it's raging obvious mirage you often cannot see anything. As an example if you get a chance to look at a target with subtle mirage with a Leupold or Weaver and then immediately go to a March....... in a word YIKES.
 
Now i certainly don't know but have some thoughts. I have been told shooting in no wind is worse than shooting in the wind. Even in this thread someone mentioned shooting in no wind does strange things.

All i shoot is rimfire so that's where these thoughts come from. A few years back i wanted to shoot but it was raining, a lite drizzle -well i shot anyway, to my surprise some of my best groups. I have since shot groups in the rain and always seemd to be a little better -now that's for me. So i ask why?? No wind won't shoot why.

Not that it matters but here is my current thinking. I think when it's a lite rain and been raining for several minutes - between the shooter and the target with rain there is just one air density ie smooth shooting -no changing the bullet path due to air density changes

With no wind i think between you and the 50 yard target you could have maybe 10 different air densities. Each air density is changing the bullet path from ever so slight to damn what happened! It would depend on clouds, shadows, and rising air from the ground depending on the reflective qualities of the ground cover. Air over grass will have a different density as air over sand just a few feet apart.

With wind you have a vehicle to stir the air and help even out the different densities... maybe with wind you would only have 2 or 3 densities between the shooter and the target.

Now i have no proof but i would guess heat rising in the summer time changes the bullet path -not the heat but the density change the heat creates. Rimfire seems pretty finicky to me maybe the slow speed the round is traveling -some 2,000 feet per second slower than centerfire makes rimfire "evil".

maybe plum stupid but that's the path my brain is on today.
joe:)
 
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thank you joe.

that has been the best damned answer i have read so far. i just wanted to ask because it was running through my mind. the answer you gave made great sense to me and now i am starting to understand some more. thank you very much for chiming in. that was a big help. you put it in plain simple english that a back woods hick like myself can understand!!!!
 
mr. nobody said:
thank you joe.

that has been the best damned answer i have read so far. i just wanted to ask because it was running through my mind. the answer you gave made great sense to me and now i am starting to understand some more. thank you very much for chiming in. that was a big help. you put it in plain simple english that a back woods hick like myself can understand!!!!
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Mr Nobody thanks for the kind words... The above offering may not be correct, just some thoughts -maybe something to keep in the back of your mind. I may get a black eye in the morning when some of the regulars wake up, lol. joe :)
 
joe,
i have a thick skin and you should to. let them beat and bash all they want. that is the best answer i have heard so far and it made damned good sense. i didn't ask about mirrage. i understand it very well. it's the heat i was wondering about.
 
Pappas Flags

Does anyone have a picture of this flag? I've seen one that Don Matzeder uses that is odd but it works. Also I've seen Marion Collier use strips of plastic trash bags for tails and I also use trash bag tails at night when we shoot Air Rifle benchrest matches.
Larry
 
jGEE said:
...The above offering may not be correct, just some thoughts -maybe something to keep in the back of your mind. I may get a black eye in the morning when some of the regulars wake up, lol. joe :)
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Hi JGee,

No black eye from this ol' boy. What you say makes sense to me. :)

A light rain, a quiet foggy day, even heavy overcast can bring some good scores.

Could I say one thing off topic. I wish some of you boys would at least put the general area of the country you are doing you shooting in in your profile. The conditions one has to deal with in, let's say Arizona, compared to here in New England, may be quite different. Please don't take offence, it just might help.

Al :)
 
jGEE,

I aree with Al, and mr. nobody, good answer. Pretty much my thoughts as well. I just put a post on another board the other day about shooting good score in the rain. It seems to equalize the conditions. Don't know or really care why, it just works. I hate dead calms, no such thing, just stuff happening you can't see on the flags.

Ken
 
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