I am very new to long distance shooting. I recently set up my Remington 700 with a leupold 4.5x14x50 and a harris bipod. I just received a new impact data book. Looking though it I found the Cold Bore section, with temp, humidity, baro, altitude, range, position, ext. I searched cold bore and understand it as your first shot (not really a cold barrel per say). Can any help me to utilize this section of the book, or is this something that I will understand the more I shoot?
Advanced Marksmanship Cold Bore Data
- Thread starter Sharpline
- Start date
Re: Cold Bore Data
Cold bore data is really something that you build up over time as you learn how your rifle shoots in different environmental conditions. The more you shoot the more you'll notice trends in where the first shot impacts compared to the subsequent shots fired and use that information to hopefully get more first round hits. Some rifle and ammunition combinatioins will have no difference between the cold bore shot and the other rounds to follow, some may shoot a little differently. I hope this helped to better explain things.
Cold bore data is really something that you build up over time as you learn how your rifle shoots in different environmental conditions. The more you shoot the more you'll notice trends in where the first shot impacts compared to the subsequent shots fired and use that information to hopefully get more first round hits. Some rifle and ammunition combinatioins will have no difference between the cold bore shot and the other rounds to follow, some may shoot a little differently. I hope this helped to better explain things.
Re: Cold Bore Data
It does, can you give me a little help so I can notice trends. How does temperature affect the bullet flight? I assume the more humid it is the larger the drop. Same with the pressure (barometer). Higher the altitude the less drop. Am I on the right track?
The compe up sheet in the book, is that similar to the cold bore?
It does, can you give me a little help so I can notice trends. How does temperature affect the bullet flight? I assume the more humid it is the larger the drop. Same with the pressure (barometer). Higher the altitude the less drop. Am I on the right track?
The compe up sheet in the book, is that similar to the cold bore?
Re: Cold Bore Data
Sort of, there are no hard and fast rules about how environmental conditions will affect the trajectory of YOUR load/ammunition out of YOUR rifle. In general terms though if it is warmer out then when you last zeroed and you are higher up in altitude you'll probably need less elevation to reach a given distance. My recommendation is to look in to density altitude in relation to long range shooting. DA essentially takes all of the humidity, temperature, and altitude information and puts it into one number. I've found that it's easier to track data that way than looking through scores of numbers trying to figure out the bullet is doing in a given set of conditions.
When you're tracking your cold bore data all you are doing is looking at where the first shot is going compared to the others. After several trips to the range, if the first shot always seems to be left 1/2 MOA and high 1/2 MOA then it can be compensated for. I don't use the IDB so I don't know what their sheets look like. Also, I don't really use separate cold bore sheets, I just make a note of where the first shot impacted in the particular target sheet that I'm using, whether it's on a steel plate or a paper target. From there I go back and look at the DA and how the dope may have been different from previous sessions in the same area. From there I can build a more accurate dope card for a given density altitude.
Sort of, there are no hard and fast rules about how environmental conditions will affect the trajectory of YOUR load/ammunition out of YOUR rifle. In general terms though if it is warmer out then when you last zeroed and you are higher up in altitude you'll probably need less elevation to reach a given distance. My recommendation is to look in to density altitude in relation to long range shooting. DA essentially takes all of the humidity, temperature, and altitude information and puts it into one number. I've found that it's easier to track data that way than looking through scores of numbers trying to figure out the bullet is doing in a given set of conditions.
When you're tracking your cold bore data all you are doing is looking at where the first shot is going compared to the others. After several trips to the range, if the first shot always seems to be left 1/2 MOA and high 1/2 MOA then it can be compensated for. I don't use the IDB so I don't know what their sheets look like. Also, I don't really use separate cold bore sheets, I just make a note of where the first shot impacted in the particular target sheet that I'm using, whether it's on a steel plate or a paper target. From there I go back and look at the DA and how the dope may have been different from previous sessions in the same area. From there I can build a more accurate dope card for a given density altitude.
Re: Cold Bore Data
Little things you will pick up on, or try as you go. My buddy and I started out the day engaging our targets through (while) chronographing as we shot. Our first (cold bore) shot of each string was consistantly 50 fps slower than the subsiquent shots in the string. As the bore warms and expands, the velocity goes up. We were working at 573 yards and did notice maybe some slight vertical stringing as the bores warmed and the velocities increased. Outside temp was 26 degrees F, full value wind @16 mph.
Little things you will pick up on, or try as you go. My buddy and I started out the day engaging our targets through (while) chronographing as we shot. Our first (cold bore) shot of each string was consistantly 50 fps slower than the subsiquent shots in the string. As the bore warms and expands, the velocity goes up. We were working at 573 yards and did notice maybe some slight vertical stringing as the bores warmed and the velocities increased. Outside temp was 26 degrees F, full value wind @16 mph.
Re: Cold Bore Data
A Kestrel will work fine as long as it has that particular feature, it'll also be a whole faster. I use a Brunton ADC Pro, which is cheaper and smaller but it has some trade offs. I don't like how it can't be turned off, I can flip the battery around but otherwise it's on all the time.
A Kestrel will work fine as long as it has that particular feature, it'll also be a whole faster. I use a Brunton ADC Pro, which is cheaper and smaller but it has some trade offs. I don't like how it can't be turned off, I can flip the battery around but otherwise it's on all the time.
Re: Cold Bore Data
The bullets are spread out vertically on the target instead of clustered together.
The bullets are spread out vertically on the target instead of clustered together.
Re: Cold Bore Data
Slight changes in impact on target vertically while using the same POA. These were small and would have still given a first round hit. I'm no expert, but I have a feeling this will be more prevalent with colder ambient temps ie the barrel starts out cold soaked (26 degrees) and warms considerably above ambient as it's being fired. Just my logic and opinion, I'm wrong alot.
Slight changes in impact on target vertically while using the same POA. These were small and would have still given a first round hit. I'm no expert, but I have a feeling this will be more prevalent with colder ambient temps ie the barrel starts out cold soaked (26 degrees) and warms considerably above ambient as it's being fired. Just my logic and opinion, I'm wrong alot.
Re: Cold Bore Data
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sharpline</div><div class="ubbcode-body">It does, can you give me a little help so I can notice trends. How does temperature affect the bullet flight? I assume the more humid it is the larger the drop. </div></div>
This is absolutely false. Humid air is lighter air and the bullet will fly better. The idea that humid air is heavier is purely a human reaction to it.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sharpline</div><div class="ubbcode-body">It does, can you give me a little help so I can notice trends. How does temperature affect the bullet flight? I assume the more humid it is the larger the drop. </div></div>
This is absolutely false. Humid air is lighter air and the bullet will fly better. The idea that humid air is heavier is purely a human reaction to it.
Re: Cold Bore Data
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sharpline</div><div class="ubbcode-body">It does, can you give me a little help so I can notice trends. How does temperature affect the bullet flight? I assume the more humid it is the larger the drop. </div></div>
This is absolutely false. Humid air is lighter air and the bullet will fly better. The idea that humid air is heavier is purely a human reaction to it.
</div></div>
Trust me....he is right on this one....
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sharpline</div><div class="ubbcode-body">It does, can you give me a little help so I can notice trends. How does temperature affect the bullet flight? I assume the more humid it is the larger the drop. </div></div>
This is absolutely false. Humid air is lighter air and the bullet will fly better. The idea that humid air is heavier is purely a human reaction to it.
</div></div>
Trust me....he is right on this one....
Re: Cold Bore Data
Chiller, not sure who you are trying to say is right (I'm assuming Lowlight), but he (Lowlight) is correct on this one; humidity has very little affect, but more humidity will cause less drop. Definitely seems counterintuitive at first glance, but true.
Chiller, not sure who you are trying to say is right (I'm assuming Lowlight), but he (Lowlight) is correct on this one; humidity has very little affect, but more humidity will cause less drop. Definitely seems counterintuitive at first glance, but true.
Re: Cold Bore Data
Think about the composition of the air. It's mostly nitrogen and oxygen.
Water vapor is composed to oxygen and hydrogen. Hydrogen is the lightest element. So hydrogen and oxygen must be lighter than nitrogen and oxygen - check the atomic numbers.
And that's why we are not kept awake at night by the sound of clouds crashing to the ground...
Think about the composition of the air. It's mostly nitrogen and oxygen.
Water vapor is composed to oxygen and hydrogen. Hydrogen is the lightest element. So hydrogen and oxygen must be lighter than nitrogen and oxygen - check the atomic numbers.
And that's why we are not kept awake at night by the sound of clouds crashing to the ground...
Re: Cold Bore Data
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">And that's why we are not kept awake at night by the sound of clouds crashing to the ground... </div></div>You mean...those weren't clouds?
Humidity does have an effect, but it's very small inside of 1000 meters:
My load at 1000m at 0% humidity - 11.2 Mils elevation.
Same load at 1000m at 100% humidity - 11.1 Mils elevation.
That's a difference I would dial, but look how much difference in humidity you would need in order to dial .1 Mil at 1000m.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lindy</div><div class="ubbcode-body">And that's why we are not kept awake at night by the sound of clouds crashing to the ground...
Humidity does have an effect, but it's very small inside of 1000 meters:
My load at 1000m at 0% humidity - 11.2 Mils elevation.
Same load at 1000m at 100% humidity - 11.1 Mils elevation.
That's a difference I would dial, but look how much difference in humidity you would need in order to dial .1 Mil at 1000m.
Re: Cold Bore Data
Which means that if you assume that the humidity is always 50%, the maximum amount you're going to be off is an amount that I can't hold.
Humidity is worth considering as a factor at extra-long range - well past 1000 yards. Inside those ranges, it may be safely ignored.
Which means that if you assume that the humidity is always 50%, the maximum amount you're going to be off is an amount that I can't hold.
Humidity is worth considering as a factor at extra-long range - well past 1000 yards. Inside those ranges, it may be safely ignored.
Re: Cold Bore Data
Sharpline,
If you spend some time searching past threads, you'll get some good information on this topic. The consensus is that a cold bore shot will not deviate from the others unless you have mechanical issues with your rifle (thin barrel, stock contact, etc.) The problem is usually a "Cold Shooter Shot" and strangely enough, it can be consistent. A clean cold bore shot is a different issue because the friction properties are different in a clean barrel due to cleaning products/lubricants being in the barrel. This is why most guys will shoot "foulers" before they shoot a string that counts. Hope this helps.
Sharpline,
If you spend some time searching past threads, you'll get some good information on this topic. The consensus is that a cold bore shot will not deviate from the others unless you have mechanical issues with your rifle (thin barrel, stock contact, etc.) The problem is usually a "Cold Shooter Shot" and strangely enough, it can be consistent. A clean cold bore shot is a different issue because the friction properties are different in a clean barrel due to cleaning products/lubricants being in the barrel. This is why most guys will shoot "foulers" before they shoot a string that counts. Hope this helps.
Re: Cold Bore Data
Yup, I read a few threads before posting. I just was seeing if there was a mathmatical area to the data. But it seems like it is trial and error. I figure the more I shoot the better handle I will have on these subjects.
Yup, I read a few threads before posting. I just was seeing if there was a mathmatical area to the data. But it seems like it is trial and error. I figure the more I shoot the better handle I will have on these subjects.
Re: Cold Bore Data
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: quattrodoc</div><div class="ubbcode-body">Chiller, not sure who you are trying to say is right (I'm assuming Lowlight), but he (Lowlight) is correct on this one; humidity has very little affect, but more humidity will cause less drop. Definitely seems counterintuitive at first glance, but true. </div></div>
I was at RO this last spring and we (Jacob, Frank, and I) were in a discussion on how humidity affects the density of air. Bottom line is after going through a Psychometric Chart and confirming that the density of air goes DOWN as the relative humidity goes UP I had the fine opportunity to eat some crow and learn a valuable lesson.
Perhaps one of the funny takeaways from this is that many books that were written on this topic have been wrong for a number of years.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: quattrodoc</div><div class="ubbcode-body">Chiller, not sure who you are trying to say is right (I'm assuming Lowlight), but he (Lowlight) is correct on this one; humidity has very little affect, but more humidity will cause less drop. Definitely seems counterintuitive at first glance, but true. </div></div>
I was at RO this last spring and we (Jacob, Frank, and I) were in a discussion on how humidity affects the density of air. Bottom line is after going through a Psychometric Chart and confirming that the density of air goes DOWN as the relative humidity goes UP I had the fine opportunity to eat some crow and learn a valuable lesson.
Perhaps one of the funny takeaways from this is that many books that were written on this topic have been wrong for a number of years.
Re: Cold Bore Data
During this particular class at RO, Chiller earned the nickname "Humidity Hugh".
However he is absolutely correct in stating that most of the shooting manuals <span style="font-style: italic">(including military sniping manuals)</span> continually repeat the wrong information and have written that humidity increases air density requiring the shooter to add dope instead of subtracting it.
Because of the minor effect humidity plays on our shot, I usually have those during databooks for me, to leave out humidity and instead replace that space with Density Altitude
During this particular class at RO, Chiller earned the nickname "Humidity Hugh".
However he is absolutely correct in stating that most of the shooting manuals <span style="font-style: italic">(including military sniping manuals)</span> continually repeat the wrong information and have written that humidity increases air density requiring the shooter to add dope instead of subtracting it.
Because of the minor effect humidity plays on our shot, I usually have those during databooks for me, to leave out humidity and instead replace that space with Density Altitude
Re: Cold Bore Data
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">During this particular class at RO, Chiller earned the nickname "Humidity Hugh".
However he is absolutely correct in stating that most of the shooting manuals <span style="font-style: italic">(including military sniping manuals)</span> continually repeat the wrong information and have written that humidity increases air density requiring the shooter to add dope instead of subtracting it.
Because of the minor effect humidity plays on our shot, I usually have those during databooks for me, to leave out humidity and instead replace that space with Density Altitude </div></div>
Time for me to tuck tail and go dry fire some more....
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">During this particular class at RO, Chiller earned the nickname "Humidity Hugh".
However he is absolutely correct in stating that most of the shooting manuals <span style="font-style: italic">(including military sniping manuals)</span> continually repeat the wrong information and have written that humidity increases air density requiring the shooter to add dope instead of subtracting it.
Because of the minor effect humidity plays on our shot, I usually have those during databooks for me, to leave out humidity and instead replace that space with Density Altitude </div></div>
Time for me to tuck tail and go dry fire some more....
Re: Cold Bore Data
rimfire....yes
Centerfire....do it to your hearts content and then do it x5 more than you thought
Rule of thumb...x10 dry fire or more for every live fire.
Are you on the Online training?
Learn it right as opposed to learning it twice....
rimfire....yes
Centerfire....do it to your hearts content and then do it x5 more than you thought
Rule of thumb...x10 dry fire or more for every live fire.
Are you on the Online training?
Learn it right as opposed to learning it twice....
Re: Cold Bore Data
If I am not mistaken humidity has very little effect on your dope until the temp climbs over 90 degrees.
If I am not mistaken humidity has very little effect on your dope until the temp climbs over 90 degrees.
Re: Cold Bore Data
Humidity has very little effect until the range exceeds 1000 yards.
To confirm that for yourself, set up a ballistics program with information about your load. Set the humidity at 10 percent, and calculate a 1000 yard shot. Then change the humidity to 90 percent, and recalculate. Observe the difference in the elevation calculation.
With my .308 load, the difference is less than 2 inches on an ICAO standard day.
And note that will you rarely observe those extremes of humidity.
Humidity has very little effect until the range exceeds 1000 yards.
To confirm that for yourself, set up a ballistics program with information about your load. Set the humidity at 10 percent, and calculate a 1000 yard shot. Then change the humidity to 90 percent, and recalculate. Observe the difference in the elevation calculation.
With my .308 load, the difference is less than 2 inches on an ICAO standard day.
And note that will you rarely observe those extremes of humidity.
Re: Cold Bore Data
Sharpline I think I can relate to the CB question, almost every time I shoot I start my session w/ a cold bore at 1000 yards, over time like ( like Triggermonkey stated ) i noticed a trend which was If I did not hit my cold bore my miss was just right of the ipsc plate that allowed me to compensate or just deductively reason to add 1 or 2 clicks left additionally to my retail values which dramatically has improved my hit ratio. I can plug numbers into my software all day but past dope over long periods for me has become much more reliable when it cones to fine tuning.
CB at 100 yards is a different gig, for me at least.
Keep good data, over long periods has allowed me insight for my situation that would be hard to find any other way.
Sharpline I think I can relate to the CB question, almost every time I shoot I start my session w/ a cold bore at 1000 yards, over time like ( like Triggermonkey stated ) i noticed a trend which was If I did not hit my cold bore my miss was just right of the ipsc plate that allowed me to compensate or just deductively reason to add 1 or 2 clicks left additionally to my retail values which dramatically has improved my hit ratio. I can plug numbers into my software all day but past dope over long periods for me has become much more reliable when it cones to fine tuning.
CB at 100 yards is a different gig, for me at least.
Keep good data, over long periods has allowed me insight for my situation that would be hard to find any other way.
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