Tuner temperature tune range?

[G7BC]

Here's an example of the results sent to me before I made up that target(above)and took a pic of it for instruction purposes.

See the group shapes I described?
10,11 and 12 are textbook clear! In this example, I'd go back and shoot around the 2 setting as well, just to verify but 10 is a safe bet.

View attachment 1504845

For what it's worth, this is the same way I test powder charges. The powder test groups will print the same type of pattern. In this example , I would load between 2 and 3 then move on to my seating depth testing where again the groups will print this type of pattern, all the while my tuner still on zero. Tuner testing would be last after my load is dialed in. Ideally I will run this test multiple times to confirm, but when short on time this can often get you ready for a match and you will be competitive. With good barrels and components , load development can be relatively easy.

 

[gunsandgunsmithing]

For what it's worth, this is the same way I test powder charges. The powder test groups will print the same type of pattern. In this example , I would load between 2 and 3 then move on to my seating depth testing where again the groups will print this type of pattern, all the while my tuner still on zero. Tuner testing would be last after my load is dialed in. Ideally I will run this test multiple times to confirm, but when short on time this can often get you ready for a match and you will be competitive. With good barrels and components , load development can be relatively easy.

Yes, you're right...it's very similar depending on charge increments.

 

[4xforfun]

Dumb ones.

Well...when it is cold 10 months of the year and you gotta work the other two, what's a man to do??

 

[JEFFPPC]

You got me, or move.

 

[Hollow-Grind]

Well...when it is cold 10 months of the year and you gotta work the other two, what's a man to do??

It is pretty rough living here with our 2 month work year lol.

 

[dcali]

Well...it's metic, so...LOL

Fun fact: -40 C is the same as -40 F.

 

[dcali]

Here's a side note that's always puzzled me. People talk about tuners changing things in different temperatures/humidity, etc. I have no idea how that's possible, but lets I'll just take it for granted.

But what about barrel temperature? The elastic modulus of steel changes slightly but significantly over a 50-100 degree range - within what you might see in an F class string. Nobody ever talks about this.

 

[gunsandgunsmithing]

Here's a side note that's always puzzled me. People talk about tuners changing things in different temperatures/humidity, etc. I have no idea how that's possible, but lets I'll just take it for granted.

But what about barrel temperature? The elastic modulus of steel changes slightly but significantly over a 50-100 degree range - within what you might see in an F class string. Nobody ever talks about this.

They talk about it quite a bit with me. Ultimately, those changes appear to get lost in the noise but are real. I believe the single largest..but not the only factor to tune, is bullet exit timing, mostly from the changes in the pressure curve created by the powder burning at different temps. It's a chemical reaction, hence is temperature dependent. The tuner being adjusted at the end of the barrel is changing phase time, not frequency. The small frequency changes induced by temp/growth are not large enough to take it to a completely different node, apparently, because even though the tune does change for more than one reason, it appears that it stays within the same nodal cycle using contours and materials typically seen in BR and F Class rifle barrels, allowing the tuner to alter phase enough within only a few marks(thousands) to correct tune by effectively moving the anti-node left or right(changing phase) to time with bullet exit. This may or may not be true with materials such as carbon fiber..IDK. I do hope to test barrels that have been cryo'd vs not, sometime in the near future, which might be a step in that direction but I have no plans yet for anything using carbon wrapped barrels.

There's plenty I don't know and it may or may not matter in terms of actual tuner use because that part is pretty cut and dry where we have sighters or other means to tune by. The real magic is IF it's possible to do so with all the other factors, simply by a formula and it be 100%. We're close to that using what we know already are seemingly the largest factors. Those being temp and air density. Temp's effect on the chemical reaction of powder turning from solid to gas is by far the biggest and easiest to understand. Air density may well affect both internal ballistics as well as influence the way the barrel vibrates. Again, IDK. But I do know those are the biggest factors and have definite effects on tune and that a tuner can correct phase time for them..tuning the rifle. I believe those two factors can be charted to achieve a very high 95ish% success tuning by. Since that's not 100%, it certainly means there are other factors and it may well involve homogeny of the steel and the resultant affect of temps on the bbl itself.

One other point to your post. We've long known that cooking a round for an extended period of time can give poor results on target. Again, I believe that supports that temp effect on powder is the biggest factor but powder being a cellulose product, is a fair insulator and doesn't change rapidly in ambient conditions vs setting in a hot chamber for a minute.

 

[CharlieNC]

They talk about it quite a bit with me. Ultimately, those changes appear to get lost in the noise but are real. I believe the single largest..but not the only factor to tune, is bullet exit timing, mostly from the changes in the pressure curve created by the powder burning at different temps. It's a chemical reaction, hence is temperature dependent. The tuner being adjusted at the end of the barrel is changing phase time, not frequency. The small frequency changes induced by temp/growth are not large enough to take it to a completely different node, apparently, because even though the tune does change for more than one reason, it appears that it stays within the same nodal cycle using contours and materials typically seen in BR and F Class rifle barrels, allowing the tuner to alter phase enough within only a few marks(thousands) to correct tune by effectively moving the anti-node left or right(changing phase) to time with bullet exit. This may or may not be true with materials such as carbon fiber..IDK. I do hope to test barrels that have been cryo'd vs not, sometime in the near future, which might be a step in that direction but I have no plans yet for anything using carbon wrapped barrels.

There's plenty I don't know and it may or may not matter in terms of actual tuner use because that part is pretty cut and dry where we have sighters or other means to tune by. The real magic is IF it's possible to do so with all the other factors, simply by a formula and it be 100%. We're close to that using what we know already are seemingly the largest factors. Those being temp and air density. Temp's effect on the chemical reaction of powder turning from solid to gas is by far the biggest and easiest to understand. Air density may well affect both internal ballistics as well as influence the way the barrel vibrates. Again, IDK. But I do know those are the biggest factors and have definite effects on tune and that a tuner can correct phase time for them..tuning the rifle. I believe those two factors can be charted to achieve a very high 95ish% success tuning by. Since that's not 100%, it certainly means there are other factors and it may well involve homogeny of the steel and the resultant affect of temps on the bbl itself.

Exactly! Positive compensation is properly matching the bullet exit time to the upward swing of the harmonic cycle. A fraction of a millisecond makes a difference.

 

[4xforfun]

You got me, or move.

Hey...ND...one of the best states to live....shoot anywhere ...at any distance......no people, and very little riff raff!!

 

[Bill Norris]

On those days where temps. soar above 90 degrees there is notable changes that require turning the tuner due to barrel heat.

Here's a side note that's always puzzled me. People talk about tuners changing things in different temperatures/humidity, etc. I have no idea how that's possible, but lets I'll just take it for granted.

But what about barrel temperature? The elastic modulus of steel changes slightly but significantly over a 50-100 degree range - within what you might see in an F class string. Nobody ever talks about this.

 

[gunsandgunsmithing]

Exactly! Positive compensation is properly matching the bullet exit time to the upward swing of the harmonic cycle. A fraction of a millisecond makes a difference.

I'm not knocking pc at all. I believe! But handloading takes most of the reason for tuning at top away with single digit es. Now rimfire is a different animal in that regard, where it might be 40fps in a decent lot of ammo. I do prefer to tune to the top either way because of pc but I use group shape to tune by so I will go to whichever side opens up more clearly, but still predictably. That catches some people by surprise when I say that but it's as simple as this...it's easier to see the state of tune if it opens more with each graduation as opposed to shooting just good enough to lose because it didn't "talk to me."

 

[gunsandgunsmithing]

On those days where temps. soar above 90 degrees there is notable changes that require turning the tuner due to barrel heat.

I won't disagree but I've not ever seen it with my guns and tuners. It's possible though with some. Leaving a round in a hot chamber is a different story. I dump it if it's been in there for more than a few seconds. And, as temp changes, how do I know if the change is from bbl heat or ambient changes? I guess I could heat the bbl intentionally, with a heat gun or similar.

 

[gunsandgunsmithing]

I shoot a lot of sighters in score matches..Always have. It's just my style of shooting and assessing conditions as well as tune at times. That said, I can't ever remember moving the tuner or seeing it go away in 15-25 shots in a 10 minute window, where it may well have been far less time than that even to finish my target, including sighters. I commonly get em down there in the first 3 minutes, including a bunch of sighters...fwiw. Bad habit, I know. Patience has left me, it seems. Lol!

 

[JEFFPPC]

Hey...ND...one of the best states to live....shoot anywhere ...at any distance......no people, and very little riff raff!!

That is all good, I agree. But as you stated, 2 months out of 12. Best part as I see it, no people.

 

[CharlieNC]

I'm not knocking pc at all. I believe! But handloading takes most of the reason for tuning at top away with single digit es. Now rimfire is a different animal in that regard, where it might be 40fps in a decent lot of ammo. I do prefer to tune to the top either way because of pc but I use group shape to tune by so I will go to whichever side opens up more clearly, but still predictably. That catches some people by surprise when I say that but it's as simple as this...it's easier to see the state of tune if it opens more with each graduation as opposed to shooting just good enough to lose because it didn't "talk to me."

Don't know how well that would work at long range????

 

[gunsandgunsmithing]

Don't know how well that would work at long range????

Easy enough. Say 8fps is worth 2" @1000. Now say you misjudged tune and it goes 3" @ 1000. But that said...like I said in my previous post, I'll go to the top if I can because pc won't happen at the bottom. FWIW 2.50-3.00 of vertical is a pretty typical scenario and it's built into the group if you miss the tune by just a little....tuner or no tuner. And that's really a best case scenario and assumes a really good gun and load.

 

[Matt_3479]

Here's an example of the results sent to me before I made up that target(above)and took a pic of it for instruction purposes.

See the group shapes I described?
10,11 and 12 are textbook clear! In this example, I'd go back and shoot around the 2 setting as well, just to verify but 10 is a safe bet.

View attachment 1504845

Hey Mike,

Still new to tuners as a whole. When you mention setting 2 and 10 are good, are you looking at group shape or position between the tunes beside them? Reason jm asking is because while 8 looks larger, poi of 8, 9, 10 are pretty similar so would 9 not be a center node In between them to give a wider window?

I guess I’m asking from the above test why is 2 and 10 your choice and not something like zero or 13, 14

 

[gunsandgunsmithing]

Hey Mike,

Still new to tuners as a whole. When you mention setting 2 and 10 are good, are you looking at group shape or position between the tunes beside them? Reason jm asking is because while 8 looks larger, poi of 8, 9, 10 are pretty similar so would 9 not be a center node In between them to give a wider window?

I guess I’m asking from the above test why is 2 and 10 your choice and not something like zero or 13, 14

No, good question! I look for a small group at both top and bottom. Being at top or bottom AND the shape of the next couple of groups, being predictable and repeatable, validates the setting. So, it's about group shape and poi. I can look at the 2 setting and see it's at top and not quite there, for one reason or another but it SHOULD be, based on how many marks away from the other sweet spot it is. Predictably, top and bottom sweet spots are about 8-10 marks apart on my tuner, as tune just repeats with the frequency. Well, we can see it has potential and that it's at the top, right. Now, re-test that area because on their own, each group is nothing more than a single 3 shot group. BUT, when it's poi and group shape are predictable, it becomes very significant statistically.

All that said...each mark of tuner movement is changing what is essentially a constant. That being how far it is from completely in tune at an anti-node, to completely out of tune at the node. That doesn't change significantly and is how I can say that 2 is worth testing more...along with the aforementioned poi and group shapes. Again, each group means virtually nothing by itself but when combined with predictable poi and group shapes following, it's VERY significant. Since we're changing a constant, I want to see clear change and there is no plausible and repeatable case where each sweet spot is valuably wider than the next, although, they might not show tune as clearly. See my previous post about that. If you can read itsmall, go with it. Myself, I need it to hit me over the head telling me the state of tune, clearly. I think that is worthwhile and especially so at short range.

 

[CharlieNC]

Easy enough. Say 8fps is worth 2" @1000. Now say you misjudged tune and it goes 3" @ 1000. But that said...like I said in my previous post, I'll go to the top if I can because pc won't happen at the bottom. FWIW 2.50-3.00 of vertical is a pretty typical scenario and it's built into the group if you miss the tune by just a little....tuner or no tuner. And that's really a best case scenario and assumes a really good gun and load.

Are you talking about the cycle of barrel movement, or poi on the target?