What distance for tuner testing?

[JFrank]

Funny, I've only shot one mid range match, my 100 yard tune was good enough to have 4 five shot groups that were smaller than everyone else.

You were fortunate on your tune and obviously a good shooter.

Jim

 

[Shooter13]

You were fortunate on your tune and obviously a good shooter.

Jim

I'm not sure about that good shooter part LOL

 

[jackieschmidt]

I am fortunate to have learned a lot through the years from some very talented Short Range Benchrest Shooters in The Gulf Coast Region.
Almost everyone agreed that if it shoots at 100 yards, it will shoot at 200 or 300 yards.

Of course, this line of thinking disregards many of the external ballistics that tend to have magnified affects on the bullets path at longer distances.

 

[Will Henry]

I have yet to use a tuner, though I have built some. With that self-confessed cluelessness out of the way, I'll show how a guy doesn't have to know anything to have an opinion.
My understanding is that the tuner is used to affect barrel vibration, thereby reducing group size. Further I suspect that tuners may be more effective in tuning for vertical dispersion. So, one can tune out the vertical at, say, 100yd so that the group is essentially flat, regardless of velocity variation. In other words, the tuner is actually compensating for velocity variation at 100yd. At 200, the velocity variation makes itself known again, although probably not enough to be a concern. At 300, it becomes noticeable. Now if the load being used has a sufficiently low SD, so that the tuner is only reducing the amplitude of vibration, (recognizing that barrel time can vary even with identical velocities. Kind of like two cars producing identical trap speeds but with one being quicker) everything will be fine from zero to wherever. If the tuner is used to tune out vertical at 400, for instance, 100 yd groups may be ugly, if the tuner is actually compensating for velocity variations.
I'm reminded of a conversation with a friend about 45 years ago. He was a long range shooter and was asking me if I thought I could get other rifles to compensate for velocity variation the way a Lee Enfield could. I didn't know but suggested that barrel weights might work. We never tried it though, and the concept of an adjustable tuner completely escaped my feeble mind.
By the way, with the wildly variable ammunition in use at the time, a good No. 4 Lee Enfield would shoot flat groups at 800m. The same rifle would produce vertical spreads of nine inches, or worse, at 200. WH

 

[gunsandgunsmithing]

I have yet to use a tuner, though I have built some. With that self-confessed cluelessness out of the way, I'll show how a guy doesn't have to know anything to have an opinion.
My understanding is that the tuner is used to affect barrel vibration, thereby reducing group size. Further I suspect that tuners may be more effective in tuning for vertical dispersion. So, one can tune out the vertical at, say, 100yd so that the group is essentially flat, regardless of velocity variation. In other words, the tuner is actually compensating for velocity variation at 100yd. At 200, the velocity variation makes itself known again, although probably not enough to be a concern. At 300, it becomes noticeable. Now if the load being used has a sufficiently low SD, so that the tuner is only reducing the amplitude of vibration, (recognizing that barrel time can vary even with identical velocities. Kind of like two cars producing identical trap speeds but with one being quicker) everything will be fine from zero to wherever. If the tuner is used to tune out vertical at 400, for instance, 100 yd groups may be ugly, if the tuner is actually compensating for velocity variations.
I'm reminded of a conversation with a friend about 45 years ago. He was a long range shooter and was asking me if I thought I could get other rifles to compensate for velocity variation the way a Lee Enfield could. I didn't know but suggested that barrel weights might work. We never tried it though, and the concept of an adjustable tuner completely escaped my feeble mind.
By the way, with the wildly variable ammunition in use at the time, a good No. 4 Lee Enfield would shoot flat groups at 800m. The same rifle would produce vertical spreads of nine inches, or worse, at 200. WH

Your logic, while shared by some, disregards that pc is there both with or without a tuner. Most of us have all seen tunes at top and bottom of a sine wave. Maybe we didn't all do a full sine test but most have seen higher speeds strike lower etc. Same thing and it happens even without a tuner. So, that would explain why some's 100 yard tune doesn't hold up at long range, even with or without a tuner.

That said, they do allow us to manipulate it where we could use a tuner to take a load that strikes low(relative to speed) and move the anti node to where that same load strikes high. And yes, at least technically, pc is yardage dependent and becomes more apparent as yardage increases. Enough to see...yes, maybe. But with ever present conditions, it gets lost in the noise inside of about 600 yards. We might have to come up a click, etc for the poi difference but move the tuner a mark or so to correct tune.

There are other factors but tuning with powder and seating allows us to change bullet exit time relative to muzzle position. Tuners allow us to change muzzle position relative to bullet exit time. So basically, same same, but two different ways to get there.

I've heard for years that tuners ONLY affect vertical but IME, that is not the case at all but due to gravity, they will have a little more effect vertically than horizontally. I'd run backward from a flat horizontal "tune" unless I'm positive it was purely in the condition. Even a "full value" 3 or 9 wind has vertical to it. There really is no wind angle that creates a true flat line. It would take a combination of wind conditions during flight...or it's out of tune. IME, the latter is more likely.

 

[CharlieNC]

I will share a story with all of you in hopes it helps the OP with his question.

Several years ago, I purchased a good F-Class rifle.

It was a 284 and after a fashion, I re-barreled it to a dasher. Dan Dowling chambered it with his proven 104 FB reamer.... I believe it is the same reamer used to chamber Mr Schatz's barrel..... the one that put the dasher on the map.

This gun shot amazingly well, you could test and see little stuff at distance. It really was awesome. I did not know how awesome it was until I sold it and bought the latest flavor of the day.

Deep creek tracker stock (Green and black Wheeler paint scheme)
Panda Action with two bolts
B&A trigger
Krieger barrels
Kelbly's rings
Ezell tuner
March HM 10-60

I won more than my share of IBS (local) 600 yard matches with it and after it had about 850-900 rounds on the barrel, I decided to get another barrel chambered and ready to go. I also had a 300 WSM barrel chambered for it at the same time.

I decided to take all my loading malarkey to the range and develop a load there in one day, it proved to be a dandy idea. I actually think @BoydAllen made the suggestion and about the hundredth time he told me that, I decided to try it.

So, with a whole day to play, I set up my gear at the range and went to work. Having already been successful with that barrel/chamber combo, I focused on that combination....... and it worked. It was about 32grains of H4895 with a Vapor Trail Bullet as I recall. After getting seating, powder, bushing, mandrel, and primer combination sorted out, I adjusted the tuner one mark in each direction to see if I could see any improvement. Nope, tuner set at zero where it was during tuning, was the best setting.

I screw the tuner all the way in and back it off a half a turn, if zero in close, I turn it to zero and leave it alone until I need it. If zero is less than 1/2 turn out, I give the tuner another full spin and bring zero to the top. I always tune with zero at the top dead center.

I shot several groups at 600 and the gun was on point, shooting sub 2" groups at 600 is good, actually really good here in Western Colorado.

Mike had explained his "Tuner Test" to me, so I cleaned the barrel and shot Mike's tuner test at 600 yards.
It did not look as pretty as the 100 yard test he uses as an example but after sending him pics, the pattern was still there.

Satisfied with my results, I loaded up all my "stuff" and headed to the 100/200 short range BR range 1/4 mile down the road.

I had just started shooting a PPC and thought they sucked!!!! What a POS! Couldn't keep that thing in tune to save my backside. So, I wanted to see if my hot shooting dasher could group at 100/200 like it does at 600 yards.

I set up all my gear and loaded some test ammo. Same rest, rifle, everything the same.
I shot a very embarrassing target. It fully looked like a bucket of yuck blew up on it. Awful indeed!!!

So, I set up to retune (powder, seating, etc.) at 100........ but wait, I have a tuner......

I loaded up the previous load and shot a three shot group, moved the tuner one mark and shot another group, so on and so forth, basically Mike's tuner test all over again.

I found a beautiful tune...... very competitive indeed. I moved the target frame to 200 yards and tried it again. The tune was good.

So I cleaned the barrel about the zillionth time for the day and loaded up more ammo. I then picked up all my gear and headed back to the 600 yard range. Knowing in my heart, I found the GOOD!

After setting up all the gear and relaxing for a few minutes knowing this could be epic, I worked up the courage to bring my best self to the line and shoot groups that would blow the doors off all my previous accomplishments.

Epic alright, epic failure.

I shot a very ugly target, tried it again, yep..... UGLY.

Turned the tuner back to the good 600 yard mark......... knotted up. Shot it again, a dandy group.

So, fast forward a couple of months, I had won a couple of IBS matches with that barrel and life was good. I attended a short range BR match at the local club and shot my usual Poorly.... me and my PPC were not friends. This was the year that the NBRSA had pooped in somebody's cheerios and none of the clubs in the region were shooting registered matches ( I actually do not know the full story but just know the match I attended was not a registered match and it normally would have been).

After my first days poor performance, I asked the Match Director ( Tom Stiner) if I could shoot my (totally out of class) dasher in the HV match on Sunday. He said, and I quote "You better, I am tired of hearing about that *&^%$ dasher!" "This is not a registered match anyway, see you and that dasher in the morning!"

Happy as a lark, I went home and preloaded some ammo. Grabbed my stuff and loaded the truck for the match the following morning.

The following morning, I reviewed my notes in my TUNER notebook (for me, this notebook is super important), and made the adjustment I had worked out previously. The first target at 200 showed it was good. I made some errors and got caught a few times, but I did come out in first place...... I absolutely had the smallest agg shot that morning. Out of class and all that, but the tune held just fine. Just for giggles, after I shot my last record target at 200, I shot a group on my last sighter target with the 600 yard setting on the tuner and it was pure yuck.

After lunch, we moved the target frames to 100 yards and got busy.

My 100 yard performance was not near as good as my 200 yard performance was, but it was good enough that I placed in the top 3 or 4 for the grand.


Based on my experience, I shoot Mike's Tuner Test at the distance I intend to compete at. Anything less, is just being lazy or frugal or both. I remind myself all the time, there is a place for lazy and frugal, but it ain't in benchrest.

I hope this helps
CW

Edit
I have had tuners save the day plenty of times. Most every barrel I have chambered is threaded for a tuner. They work, if you are willing to put in the effort to learn how to use them.
CW

To me this jives with reports by @tom regarding load optimization at long range, whereby that load is not the optimum for shorter distance. Which makes complete sense to me.

 

[Bill Norris]

I am fortunate to have learned a lot through the years from some very talented Short Range Benchrest Shooters in The Gulf Coast Region.
Almost everyone agreed that if it shoots at 100 yards, it will shoot at 200 or 300 yards.

Of course, this line of thinking disregards many of the external ballistics that tend to have magnified affects on the bullets path at longer distances.

I believe the magnified affects of external ballistics does come into play with tune even at the 200 & 300 yd. line. My reason for this is with two of my B R rifles 6BRX and 30BR I have left my 100 yd. hole in the woods shooting one ragged 1/4 inch or less group and went over to SVT_Tactical's 300 yd. range and found I needed to turn the tuner 1 value with each rifle to regain the tune.

 

[gunsandgunsmithing]

I believe the magnified affects of external ballistics does come into play with tune even at the 200 & 300 yd. line. My reason for this is with two of my B R rifles 6BRX and 30BR I have left my 100 yd. hole in the woods shooting one ragged 1/4 inch or less group and went over to SVT_Tactical's 300 yd. range and found I needed to turn the tuner 1 value with each rifle to regain the tune.

Were conditions absolutely identical? Did it go to straight vertical when it was one mark away from in tune? Was it tuned to the top or to the bottom. Those things appear at both but more so at bottom. Negative compensation!

 

[tom]

To me this jives with reports by @tom regarding load optimization at long range, whereby that load is not the optimum for shorter distance. Which makes complete sense to me.

Yes, and sometimes it does get confused with it won't shoot at (100) which not what I mean to imply. It's just a different tune, for the distance. And it needs to shoot in whatever the conditions are, that's the point, and that's when you KNOW it works. No sense in overcomplicating something that really is a simple as that.

Tom

 

[gunsandgunsmithing]

Yes, and sometimes it does get confused with it won't shoot at (100) which not what I mean to imply. It's just a different tune, for the distance. And it needs to shoot in whatever the conditions are, that's the point, and that's when you KNOW it works. No sense in overcomplicating something that really is a simple as that.

Tom

Are you saying that a good tune doesn't change with atmospheric changes?

 

[tom]

Are you saying that a good tune doesn't change with atmospheric changes?

When it's really right it really hasn't, so yes. I mean stuff that is capable of never before seen results. That's not every barrel, or I failed to find it on those that are just "good". All from my perspective for a real narrow minded goal of course.

Tom

 

[gunsandgunsmithing]

When it's really right it really hasn't, so yes. I mean stuff that is capable of never before seen results. That's not every barrel, or I failed to find it on those that are just "good". All from my perspective for a real narrow minded goal of course.

Tom

There's some physics involved but I do agree that some combinations show changes less than others. The short range group guys have loaded at the range to keep up with tune changes, forever. The physics... in simplest terms that I can state...smokeless powder, turning from a solid into a gas is a chemical reaction and every chemical reaction on earth is temperature dependent. There are other factors but temp is the biggie, by about a 4:1 ratio. So, I guess my only question is, why would a chemical reaction that affects bullet exit time, not affect tune. I do understand that some combinations show it less and that the discipline matters, a lot. If the change in tune can't be seen or is within the conditions at whatever yardage, I can certainly see where it would seem like tune never changed.

I can understand why conditions WOULD affect tune but but I can not explain how they would not. So, I'm open to learning. That would be huge! It would prove all that I've learned, read and tested to be untrue. Or at least, I'd have to really re-think a lot of what I've found.

I just spoke with a top sr shooter earlier today who said that he never thought he needed to move his tuner. He went on to say that he tuned in 34°ish temps and tested again recently and it had gained 30fps in our 94°+ summer heat and he said that yes, he did. That he had overlooked it during the seasonal change, even at sr. He was re-testing his old lot of powder before changing lots...not after. Bottom line, his same load and powder lot had gained 30fps. Would that affect your tune? It'd take a very special bbl to hide that. I told him that it should mathematically be out, and it was. As confirmed by him. fwiw.

I also understand that there are areas of the country that may not see drastic temp changes but rather, air density changes that also affect tune. Bryan Z did tuner testing(multiple tuners) in that regard a couple of years back in Wa state, where he saw very little temp change but fairly large changes in air density. Both are factors to tune, IME. That also explains why it's not temp alone. Air density works opposite to temps and just because the temp goes up does not mean that the air gets less dense...at least not at the same rate from day to day and why tune may change pretty drastically today but not tomorrow, over the exact temp swing.

 

[Alex Wheeler]

When I shot rl15 it would move about .1 per 10 degrees. With many other powders it doesnt move at all. H4895 is a good example. Varget is also good. H4350 is good. N570 is good. In fact I would say most popular powders are good. Im not that experienced with the ppc but every time I have ran powder charges in the ones I have tuned they wanted the exact charge to the kernel. Tom went to Ga. in 2016 for the 1k nats with a dasher, and his loading equipment. It wanted the same load in humid hot low altitude GA as it did in high dry cold Mt. It won the nats with the same load, could have just pre loaded. A lot of guys do load at deep creek similar to short range. Powder charge and sesting is checked every match. But changes are so small when and if needed. You would never move .3 on a powder charge. I cant explain to you why but good tunes just dont seem to move much.

 

[CharlieNC]

For a given change in velocity a ballistic calculator shows the effect is different as a function of distance, atmospheric conditions, etc. This can be expressed as the ballistic slope = moa per fps. and the results are greater at longer range as expected.

I have used the method reported by Vaughn to determine the barrel vibration based on the commonly used ladder test to show point of impact on the target, which can also be expressed vs the associated velocity to obtain the harmonic slope = moa per fps. This results in the sine wave as the barrel vibrates up/down.

To utilize positive compensation it is desired to load where the bullet exits during the upswing. The result is target slope = ballistic slope - harmonic slope. Ideally the harmonic slope completely cancels out the velocity effect, but that does not necessarily exist or it is limited to a very small charge (velocity) range. Conversely if the bullet exits as the barrel is on the down swing, negative compensation results to magnify the velocity differences. The vibration is a sine wave "curve", not a line such as a saw tooth.

So because the effect of velocity variability increases at longer distances, the degree of barrel harmonic needed to cancel or mitigate that effect also change. The question is not whether the "tune" needs to be different, but if the rifle/tuner/load can be adjusted properly for the job.

 

[gunsandgunsmithing]

When I shot rl15 it would move about .1 per 10 degrees. With many other powders it doesnt move at all. H4895 is a good example. Varget is also good. H4350 is good. N570 is good. In fact I would say most popular powders are good. Im not that experienced with the ppc but every time I have ran powder charges in the ones I have tuned they wanted the exact charge to the kernel. Tom went to Ga. in 2016 for the 1k nats with a dasher, and his loading equipment. It wanted the same load in humid hot low altitude GA as it did in high dry cold Mt. It won the nats with the same load, could have just pre loaded. A lot of guys do load at deep creek similar to short range. Powder charge and sesting is checked every match. But changes are so small when and if needed. You would never move .3 on a powder charge. I cant explain to you why but good tunes just dont seem to move much.

That can certainly happen, even at a totally different node(anti-node), but either way...it can happen. Tune repeats. There's not just a single sweet spot that magically happens, thankfully. If so, it'd be like hitting the lottery to make any gun shoot well. Endless testing with nearly infinite combinations. Instead, we know a range that works across a wide range of gun variables.

 

[Alex Wheeler]

That can certainly happen, even at a totally different node(anti-node), but either way...it can happen. Tune repeats. There's not just a single sweet spot that magically happens, thankfully. If so, it'd be like hitting the lottery to make any gun shoot well. Endless testing with nearly infinite combinations. Instead, we know a range that works across a wide range of gun variables.

With all the stuff I have messed with the powder nodes are 3% apart and most of us will try the top two nodes. Usually one is better than the other, usually it holds up better in match conditions. They are not the same tune just repeating. If we see two spots closer than the 3% one is lying to us and you have to repeat the test to know which one. Once we settle on a reamer, barrel, and components, assuming you dont change lots you almost dont even need to test powder charge once you have it all figured out. Not all barrels are consistent enough to do that, but Bartliens have been.

 

[gunsandgunsmithing]

With all the stuff I have messed with the powder nodes are 3% apart and most of us will try the top two nodes. Usually one is better than the other, usually it holds up better in match conditions. They are not the same tune just repeating. If we see two spots closer than the 3% one is lying to us and you have to repeat the test to know which one. Once we settle on a reamer, barrel, and components, assuming you dont change lots you almost dont even need to test powder charge once you have it all figured out. Not all barrels are consistent enough to do that, but Bartliens have been.

So, there's just one magical spot that shoots or is it there's one spot that shoots within conditions at 1000 yards? It seems like it'd be a lot easier to pinpoint spots at 100 yards, with about 100x less wind and noise...then fine tune if needed. Not saying that you don't need to test tune at your distance, but that there's shat ton of noise between here and 1000 yards away..by at least a factor of 100x. One thing I'll say is that there is a lot more room to learn lin LR than in SR, in regard to this. I'm not sure we'll ever get passed the value of conditions and how they relate to tuning. So, conditions don't affect powder/tune?

The rest is subjective but temp effect on powder is not. It seems almost like you're saying that tune doesn't matter much at 1000, as long as you're close. Maybe so, depending on conditions, etc. Tune is always less critical when conditions are worth more than tune, though...regardless of distance. It becomes less critical as distance increases.

I wouldn't greatly disagree with your 3% statement. I'd call it more like about 4% but that's splitting hairs a bit.

 

[Alex Wheeler]

Its conditions, its also distance, bullet stability, and trajectory. A lot of things are happening at 1k yds you dont see at 100. A lot of guys that dont shoot 1k think we would be better off tuning at 100. It does make sense. But do guys really think we have not tried that? I mean theres a reason we go through the hassle to tune at 1k. Its not because its easy. Theres something that happens around 7-800yds. Shorter than that the short range tunes hold up a lot better. Im not saying with a great barrel your 100 tune wont shoot at 1k. But if you want every barrel to shoot at 1k, you need to tune it there. Im basing this not just on my experience but a lot of customers. I believe it has a lot to do with PC but I dont need to die on the hill of why. I like to just do what works.

 

[gunsandgunsmithing]

Its conditions, its also distance, bullet stability, and trajectory. A lot of things are happening at 1k yds you dont see at 100. A lot of guys that dont shoot 1k think we would be better off tuning at 100. It does make sense. But do guys really think we have not tried that? I mean theres a reason we go through the hassle to tune at 1k. Its not because its easy. Theres something that happens around 7-800yds. Shorter than that the short range tunes hold up a lot better. Im not saying with a great barrel your 100 tune wont shoot at 1k. But if you want every barrel to shoot at 1k, you need to tune it there. Im basing this not just on my experience but a lot of customers. I believe it has a lot to do with PC but I dont need to die on the hill of why. I like to just do what works.

No argument there, man. I've always said to test your 100 yard tune at 1000 and adjust as needed, but you'll be close there. Yes, I think it's pc at play which is yardage dependent. At least in theory and IME, that's true. You're not starting from scratch and you developed a base setting with 100x less noise from which to start. And if we're talking tuners. ya should know which way and by how much to move it, regardless of distance but based on group shapes at 100, with less noise, giving more reliable results to work from. Pretty simple in that regard.

 

[quest450]

tuning at 100yd for 600 and 1K is a waste of barrel life and components IMO
there's a reason why most of us test and tune early am and late in the day to minimize the noise, I tune in South FL heat and never preload before a match when I travel but I always ended up shooting the same load and seating depth as I tested at home.......leave your wind flags and tuners at home