What has the change in tune been for a 10* or more change in temp. from the temperature that the tune was developed at? Anybody have a good rule to go by?
Ed
Ed
Tuning Temperature effect on tune
- Thread starter efoleyjr
- Start date
Some say none. I know of some that watch in 3 degree increments. That doesn't mean they always move their tuner, but they may try a click to see what happens. It also doesn't mean you move your tuner progressively in one direction for each variation.
Avoid anyone that tells you there is a hard and fast rule. You will just have to find what works for you, your gun, and ammo. If I have said it once I have said it a thousand times. There is no shortcut but putting in the work to find out what works for you.
Avoid anyone that tells you there is a hard and fast rule. You will just have to find what works for you, your gun, and ammo. If I have said it once I have said it a thousand times. There is no shortcut but putting in the work to find out what works for you.
Scientifically speaking thermal expansion of 416R SS is 5.5" x 10^-6 per inch per degree F. So on a 25" barrel, growth of length is +/- 0.001 of 8 degrees of change or 1 tuner click. But in my very limited experience, RFBR is black magic not science.
My answer may not be what you want to read...
Shooting in Portugal, during summer, can lead to more than 20º C difference between early morning and 2pm...
Be aware of barrel temp and leave your tuner alone.
Shooting in Portugal, during summer, can lead to more than 20º C difference between early morning and 2pm...
Be aware of barrel temp and leave your tuner alone.
20°C is a huge temperature swing.
In the States that would be like going from 50°F at 0600hrs to 88°F in the course of eight hours.
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I shoot in the high desert where in the summer it is 100+ in the winter as low as 32-34 degrees. same ammo same rifle no change in tuner settings. the only thing I see is higher POI in the summer temperatures. but not enough to make any scope adjustments.
Lee
Lee
Our ARA matches last about 3 to 4 hours and it's not unusual for us to have a 25 to 30 degree swing in temperature in that short period of time.
I have yet to change my tune during a match.
I have yet to change my tune during a match.
Thanks to all for your input. I was testing/tuning the other morning and was forecast to be 55* at 9am but it was 42* and previous tunes were enlarged. Previous tunes were shot at around 55* so I moved the Harrell tuner out 1 click, 0.001", and the groups went back to normal size. After around 50 min. the temp had gone up to mid 50's and the old tune setting were good again. Just wondering if the reason groups opened up was "cold" equipment or lower temperatures. The end result was that 0.001" movement on the tuner made a significant improvement in grouping. Go figure.
Ed
You got a like from the resident “ non competing” tuner whisperer. One day, one test, one click, improvement ?
Perhaps, listen to the world champion shooter instead, when tuned( assuming done correctly to begin with) leave the thing alone and concentrate on learning to read condition.
P.S. You know what you’re going to learn when it’s 42deg ??? You’re hands get cold.
Perhaps, listen to the world champion shooter instead, when tuned( assuming done correctly to begin with) leave the thing alone and concentrate on learning to read condition.
P.S. You know what you’re going to learn when it’s 42deg ??? You’re hands get cold.
Tim, as much as you are a know it all, you don’t know it all. There are guys on here I would put up against anyone who have held actual records in ARA that move their tuners in a match. Nothing against Pedro, he has his view, but it isn’t absolute.
Quit being the keeper of all that is right and all that is wrong at the same time. And knock off taking shots at people in every post. It’s been old for a long time and I have had enough of it. Leave the personal crap out of it. Last warning.
Quit being the keeper of all that is right and all that is wrong at the same time. And knock off taking shots at people in every post. It’s been old for a long time and I have had enough of it. Leave the personal crap out of it. Last warning.
Maybe, read what I post.
Could care less what, how, when, seasoned guys do with their tuners.
The principle argument is for brand new guys just starting out, learning tuning, making it way harder than it needs to be, way too early in their learning curve.
Shots in every post????? I don’t care care what your position is, you owe me an apology.
Could care less what, how, when, seasoned guys do with their tuners.
The principle argument is for brand new guys just starting out, learning tuning, making it way harder than it needs to be, way too early in their learning curve.
Shots in every post????? I don’t care care what your position is, you owe me an apology.
Not going to happen. You can decide to stay or go with your actions.
Thank God I don't have to learn my lessens from you. I have been doing this shooting thing, holding the gun, since the 1965 Nationals and have more than likely forgot more than you know, but not everything. O by the way I CAN read the condition also and lived most of my life in snow country so I know alot about what 42* and less is all about. Say good night Gracie
P.S. I spent 50 yrs hanging out with World Champion Position shooters and actually got good info from them.
Without exception, smokeless powder turning from a solid into a gas is a chemical reaction. And again without exception, every chemical reaction is temperature dependent. This is just life and not something that I consider to be debatable nor am I looking for debate. But I would like for more people to actually become aware of this fact. I won't go into how it affects tune here. If you acknowledge this to be true, I'll respect that you can reason, that tune changes because of it. Maybe not a lot, maybe a lot...but physically, there is a real reason to expect it to change because of physics. Expecting a single setting to be in tune throughout these changes in exit time seems counter to physics, to me. This is my opinion and it is backed up by vibration analysis and extensive testing. Bullet exit relative to muzzle position is IMHO, what tuning is all about. Anything that affects bullet exit time relative to where the muzzle is when the bullet exits the barrel, affects tune. I'm not a physicist and I'm not a national champion RF shooter but I do read, test and do my very best to understand this small area of a very broad subject. Again without exception, what I have said has proven to be true to the science. I will say that some tunes do appear to be broader in terms of how they print on target as they progress away from peak tune. Some get very noticeably bigger while others change, but not as dramatically. That's a double edged sword. If you follow my posts or we have discussed this, you know that I actually prefer a tune that "talks to me." To do that, I want it to change clearly rather than shooting good but not great, even when slightly out of tune. Similar to the heavy bbl thread on here or on accurate recently. Heavier bbls do tend to show tune less clearly than a bit less stiff bbl does. It's up to you which you prefer but jmho, I find it easier to stay at a peak tune with a bbl that prints group shapes very clearly as opposed to one that shoots just good enough to get beat, even when a small bit out of tune. That's my 2 cents on that but I think the logic is pretty clear as to why a stiffer bbl shows tune differently than a less stiff one, without a lot of explaining.
To anyone that disagrees... I may be over simplifying things with my above statements but the testing says otherwise.
There are certainly things that I do not know that do factor into tuning. It's really a very complex system with lots of moving variables. So I'm very content to say that sometimes, I simply don't know everything but I don't argue with what has been well established as factual science, but I do test and try to learn/understand that science and more about all of the possible variables without limiting myself to only accepting the results of top shooters, who were likely top shooters, either way. Sometimes we do things without knowing why it works but doing things that we know are counter to science should be understood as to why., at the very least. But who knows...maybe there is more to it than we know at this day and time, and shooting rf rifles might be what turns Isaac Newton over in his grave. More likely though, there's a reason why what we do works or doesn't that has already been explained without any black magic, but physics.
JMHO, but none of this is magic. There's a lot of skill and a lot more science to it than meets the eye but I don't buy anything being sold as art without science...ie magic. Anyone is free to disagree and I expect it, but I admit that I find it hard to understand why. IME, everything I've said has been easily verified with a good rifle and a little research on the subject. The biggest issue I find is misuse of tuners by moving too much at a time. It's a shame that the most popular tuners don't come with any instructions for actually using them to tune a rifle.
To anyone that disagrees... I may be over simplifying things with my above statements but the testing says otherwise.
There are certainly things that I do not know that do factor into tuning. It's really a very complex system with lots of moving variables. So I'm very content to say that sometimes, I simply don't know everything but I don't argue with what has been well established as factual science, but I do test and try to learn/understand that science and more about all of the possible variables without limiting myself to only accepting the results of top shooters, who were likely top shooters, either way. Sometimes we do things without knowing why it works but doing things that we know are counter to science should be understood as to why., at the very least. But who knows...maybe there is more to it than we know at this day and time, and shooting rf rifles might be what turns Isaac Newton over in his grave. More likely though, there's a reason why what we do works or doesn't that has already been explained without any black magic, but physics.
JMHO, but none of this is magic. There's a lot of skill and a lot more science to it than meets the eye but I don't buy anything being sold as art without science...ie magic. Anyone is free to disagree and I expect it, but I admit that I find it hard to understand why. IME, everything I've said has been easily verified with a good rifle and a little research on the subject. The biggest issue I find is misuse of tuners by moving too much at a time. It's a shame that the most popular tuners don't come with any instructions for actually using them to tune a rifle.
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The real issue with almost all these discussions is that we never see any data. A shooter moves his tuner one click and gets positive results. How about the thousands of times a shooter moves his tuner one click and gets no results, or even bad results. What I want to see is data that leads to repeatability and predictability.
If real science is working it is one thing to tell me what is happening with your rifle and quite another to tell me what is happening or will happen with my rifle.
If real science is working it is one thing to tell me what is happening with your rifle and quite another to tell me what is happening or will happen with my rifle.
Agree that every chemical reaction is temp sensitive. But is that temp reaction enough to affect the bullet velocity enough to vary the tuner setting. I have no idea. Now is the temperature of the barrel more important than the chemical reaction variance? Again, no idea but I suspect it is. I may play a bit with this soon now that I have my Garmin chronometer. Have to justify buying this thing somehow. 
Put bullets in baggy in ice water and shoot. Put bullets in hot water in baggy and shoot. Of course I'll measure the temperatures of the bullets with my meat thermometer. Might try this tomorrow before a match. But from what I've seen already on variability of velocity from the same lot I don't know if it will prove anything. And the barrel will be at ambient temperature for both. Like these discussions, Mike always has something neat to say.
Put bullets in baggy in ice water and shoot. Put bullets in hot water in baggy and shoot. Of course I'll measure the temperatures of the bullets with my meat thermometer. Might try this tomorrow before a match. But from what I've seen already on variability of velocity from the same lot I don't know if it will prove anything. And the barrel will be at ambient temperature for both. Like these discussions, Mike always has something neat to say.Keep in mind that technically, velocity doesn't have to change to affect tune. If the pressure curve is different, the in bore time may well be different as well, even at the same speed at the muzzle.Agree that every chemical reaction is temp sensitive. But is that temp reaction enough to affect the bullet velocity enough to vary the tuner setting. I have no idea. Now is the temperature of the barrel more important than the chemical reaction variance? Again, no idea but I suspect it is. I may play a bit with this soon now that I have my Garmin chronometer. Have to justify buying this thing somehow.
As to barrel temp vs ambient...I find ambient to be most critical. I suspect simply because powder being a cellulose product, it's a decent insulator and doesn't change rapidly. I think if you let a round cook in a hot chamber for long enough, it will likely affect it though. I hope you'll post your results.
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warm ammo versus cold ammo. Do not know about effecting tune but more than one shooter on cold days will keep ammo in their pants pocket making sure the rounds are on the warmer side.
I know one shooter at Novembers 50/50 match kept activated hand warmers in case holding their ammo. And finished better than average. Did this affect his outcome? Most likely not.
I know one shooter at Novembers 50/50 match kept activated hand warmers in case holding their ammo. And finished better than average. Did this affect his outcome? Most likely not.
I tried not to get into what will happen to your rifle and stay strictly with non-debatable facts, intentionally. The effect is more debatable for various reasons. But, virtually everyone uses a tuner for some reason. I do lean toward it being explicable rather than believing in magic or any single setting that magically brings everything into perfect harmony through all conditions and in bore time changes with different lots etc. True, some lots are better than others but what about tuning to those lots or tuning to lots that maybe didn't shoot well at the same setting as another lot?
In cf we get to play with all sorts of variables to tune with but it's very common to get equally good results from totally different loads and components, at different speeds and all manner of different variables.