Getting There From 50 to 100 on the Tuner!

[Enosiophobia]

Bullets moving at different velocities will not exit the muzzle at the same time, but if they could leave when the muzzle is "stopped" at the top or bottom of the vibration, then those velocity differences would impact at different vertical due to ballistics. I think Kolbe coined the term positive compensation, and with an instrumented barrel showed a tuner changes the exit time such that faster bullets exit earlier when the barrel is pointed at a lower angle, and slower bullets exit later when the barrel is further on the upswing of harmonic movement. In this case the harmonic effect offsets the ballistic effect to reduce the effect of velocity; the challenge is to find the proper tuner weight and adjustment to achieve the exact offset.

But using a ballistic calculator, we know the effect of velocity differences on drop depends on the distance., Meaninging the necessary harmonic offset from the tuner is also different based on distance. But there are too many variables to simply calculate this, except to know it is not exactly the same and a good tune is still better than no tune across distances.

Do we assume barrels only vibrate in a vertical motion?

 

[CharlieNC]

Do we assume barrels only vibrate in a vertical motion?

No.

 

[Hi-NV Shooter]

When i was at the Test Center.. when Lucus was doing it there in Ohio. He made the statement that some lots shoot better at 100 than others. What he was referring to was, that there are many lots that shoot excellent, to same at 50.. but shoot differently at 100. So as to what John is saying from his observations, it may be that changing the tune at 100 might help those lots shoot better at 100..
And as you say.. you shoot some score at 100.. but well as.. most RF BR guys.. only shoot at 50 and are not concerned about how it shoots at 100 or never do shoot at 100. I wonder how many folks have had lots like what Lucus is referring to.. Excellent at 50 but so so at 100.

Ok now I understand what you are talking about. yes, it would be interesting, and I think the reversal should be tried. tune a rifle at 100 first then see what results are at 50 with the same lot.
Mr. Whidden has the perfect set up to do this. logically if a rifle can be made to shoot at 100 yds. shouldn't the results be good at 50 with the same tuner setting?

As for what was said about lots shooting excellent at 50 and not at 100 where some do both would be interesting to know if the ones that fell apart at 100 shot equally as well at 50 as those that could do both.
meaning say a lot shot 11mm at 50 and 19mm at 100 would one of those other lots that shot excellent at 50 and fell apart at 100 were they able to produce the same or better 11mm at 50?

I have never seen this myself in general if it shot good at 50 and used at 100 the results, I saw were expected based on what I saw at 50.

I guess the best way to see if it is truly ammo driven is to look at results from rifles tested with no tuner were the groups at 50 an indication of what to expect at 100.

Lee

 

[10XSHOOTER]

Just got a new case of Center-X. Took it to a local indoor range that has 100 yds. Using my Turbo with a Harrels tuner. Started at Zero at 50 yards. made one full turns and shot 3 rounds. amazing to see how it changed the group. best groups were at 25 and 125 at fifty yards on the tuner. then went out to 100 yds and did the same thing. More amazing at groups there. ended up with a tuner setting of 125 also had that setting at 50 yds. So came back to 50 and verified the setting at 125 at fifty. Going to leave the tuner there!

 

[Ranger188]

I think some ammo will shoot good at 50 and will fall apart at 100
if the ES is not as consistent as another. Been their done that.
It will definitely show more as the distances increase due to it's only starting at
1050 + - fps and much of a change will affect it's drop even more.

 

[gunsandgunsmithing]

As Mike suggested.. let's discuss tuner variations. Movement of the tuner direction and results one has obtained in different distance settings. Namely, the difference between 50 and 100 yards. I have heard this on several occasions that one could benefit from using two different tunes for each distance. So my curiosity strikes me to want to know more about it and why this might be the case. Please substantiate your statements with facts.. not your keyboard opinions. Thanks

This is for rimfire, not cf..fwiw. There are small differences between them but nothing huge.

I'm gonna keep this very short. Got a dying family member and no time to debate but I'll just say, why not simply test a few marks on both sides of a sweet spot at both distances. IME, the difference between 50 and 100 is not a lot but with some guns and some ammo, 2 marks on my tuner is about right to correct it. (the harrells is pretty similar IME) And what you will normally see, that isn't wind induced, is vertical in those 2 marks difference. So, if it'd dead nutz in tune at 50 but a bit of vertical at 100, move it 2 marks either way and try it. You'll quickly learn which way is right on your gun. Same goes for learning the next few groups in 2 mark intervals. Just try it but go no more than 2 marks at a time for about 15 groups of five. Ideally, do all groups on the same horizontal plane, so vertical poi changes are clearer, Some guns show this change clearly while some do not, especially rimfire. I'll post a pic of the target I use in a minute. It really shows me everything I look for. Maybe most importantly, it shows the value of each incremental change and how those changes show up on the target. When done, go back and test 1 mark for a few groups around the sweet spots that you find in that 15 group test. You may very well find improvement with just 1 mark.

 

[Jefferson]

When i was at the Test Center.. when Lucus was doing it there in Ohio. He made the statement that some lots shoot better at 100 than others. What he was referring to was, that there are many lots that shoot excellent, to same at 50.. but shoot differently at 100. So as to what John is saying from his observations, it may be that changing the tune at 100 might help those lots shoot better at 100..
And as you say.. you shoot some score at 100.. but well as.. most RF BR guys.. only shoot at 50 and are not concerned about how it shoots at 100 or never do shoot at 100. I wonder how many folks have had lots like what Lucus is referring to.. Excellent at 50 but so so at 100.

so is that the case or is the question

does positive compensation at one distance change at another ?

answer yes but not by bloddy much

 

[Hi-NV Shooter]

so is that the case or is the question

does positive compensation at one distance change at another ?

answer yes but not by bloddy much

Maybe I misunderstood what Positive Compensation means as it relates to rimfire. but if you truly achieve PC why would distance changes affect it?
my understanding is that PC will flat line slow and fast rounds so they intersect and have same POI meaning if I shot 10 lots of various speeds, they all should have same POI.
therefore, distance should only affect POA to POI meaning adjusting POA is all that would be needed.
PC should not have changed.

Lee

 

[Hi-NV Shooter]

Just got a new case of Center-X. Took it to a local indoor range that has 100 yds. Using my Turbo with a Harrels tuner. Started at Zero at 50 yards. made one full turns and shot 3 rounds. amazing to see how it changed the group. best groups were at 25 and 125 at fifty yards on the tuner. then went out to 100 yds and did the same thing. More amazing at groups there. ended up with a tuner setting of 125 also had that setting at 50 yds. So came back to 50 and verified the setting at 125 at fifty. Going to leave the tuner there!

Next test is to see how many different lots will shoot the same as the one you used to tune with. if you see very little to no difference then I would say you are there.

Lee

 

[Hoser]

I have an older lot of Eley Biathlon. Shoots incredible at 50 yards, 10 shots under 3/8 of an inch. At 100 yards I am lucky to get all ten to stay under 1.5 inches. Adjusting the tuner did not help the 100 yard accuracy.

 

[PNW Skipper]

of course you've not.. prob cuz this subject was never brought up.. and no one ever tried it.. just a thought

Or, more likely. because the experience (9 match/year, 8 shooters/match avg, 5 years -> sample set of 360) suggests that a tune that shoots good at 50, shoots good at 100. Interestingly, there are usually a few Win 52's and Rem 37's in the hunt, WITHOUT tuners, that also occasionally win matches, further supporting the premise of changing tune between distances not being critical.

I think the more meaningful experiment would be to take a rifle with a tuner, and no matter what you have done with it previously, tune it at 100 yards using the same practice you would for setting up your tune from scratch for a 50 yard BR match. Then move in to 50 yards and see if that tuner setting still shoots well. From my experience, I would bet it will. But since I've already seen it demonstrated in these matches, I don't see the need to spend good ammo and time on the exercise.
My personal best each year kind of demonstrates the range in the data set:
2019: Win52A (stock HB), no tuner, Vortex GE, Lapua CX, 397-28X
2020: Stiller 2500, Harrels, Leupold 40X, Federal UM-22, 400-35X
2021: Eck Turbo, Harrels, Hawke 10-50X60, Eley Tenex, 399-30X
2022: Walther KK500, Starik, Leupold 40X, Eley Tenex, 398-30X
2023: Kenyon Rem 37, Hoehn, Unertl 30X, Eley Match, 399-28X
2024 (YTD): 398-30X, Stiller 2500, Harrels, Leupold 40X, Lapua SLR, 398-30X.
I have shot scores in this same range with other tuned rifles such as an Anschutz 54 w/ Hart barrel, a Kleinendorst Win 52D, and a Calfee Turbo.

FWIW, and so others can understand how my tuning/competition practices should be considered with this info, I tune at 50 yards, generally following Mike Ezell's method, except that I will shoot 3 tuning sets using 3 different ammo brands and a range of rated velocities. I then graph the results and pick a setting in the middle of settings that result in symmetrical groups with minimal vertical dispersion for all 3. Usually I can find a spot where that happens within 2-4 clicks for all 3. Then I record, set, and leave that setting. I bring a selection of ammo to each match and shoot the one that shoots best in warmup in that day's environment. So essentially my final tuner setting is "close enough" for a range of ammos, and the final tune is accomplished with ammo selection at the match. For me, it's simpler than trying to remember how many clicks to adjust, in which direction, for which ammo, in what environmental conditions. When shooting a match like the Dewar that has two different ranges, I select ammo at the match based on performance at the longer range.

Not saying it's "right." Just what works reasonably for me.

of course you've not.. prob cuz this subject was never brought up.. and no one ever tried it.. just a thought

 

[CNC-Dude]

of course you've not.. prob cuz this subject was never brought up.. and no one ever tried it.. just a thought

I'm wondering how many setup their tuner to shoot good at 50 yards, and it also shoots pretty good at 100 yards....and just accept that as is without trying to tweak the tuner to make it shoot better at 100 yards instead of just pretty good?

 

[grauhanen]

If positive compensation works so that faster and slower rounds converge at a single POI at 50 that means their trajectories intersect at that distance. In other words, faster and slower rounds must have different trajectories from muzzle to get to the same POI at 50.

It would seem to follow that rounds with different MV's yet the same POI at 50 must begin to diverge once past 50.


_________________________

On a more practical level, regardless of how tuners actually work shooters wishing to use tuners should have as realistic appreciation as possible of what tuners can achieve.

When perfectly set how much improvement can tuners be expected to give at 50? Will they "shrink" groups by 10%? 20%?

 

[gunsandgunsmithing]

I'm wondering how many setup their tuner to shoot good at 50 yards, and it also shoots pretty good at 100 yards....and just accept that as is without trying to tweak the tuner to make it shoot better at 100 yards instead of just pretty good?

Understanding pc and tuners a bit really helps put a number to that, answering your question, mostly. Because pc can only occur at top of bbl swing but the gun can shoot well at top and bottom, that alone would suggest 50% on the surface. But then you have a fair number of people that tune for different ammo speeds to hit the same poi, which is in fact tuning for pc.

Step one, with any tuner, should be to learn the value of each increment and how it changes the group size and shape. Without knowing that info, no other way to say it...you're guessing and hoping to land on a sweet spot. My tuning method is about breaking it down into small incremental moves and establishing a constant value for those movement of the tuner. It's not earth shaking or new, it's just more methodical than moving in some random or large amount and honing in on a spot that shoots small, leaving most people without knowing what a few marks either will will do to tune and even if you are at top or bottom(pc). So, it's actually pretty easy to understand why there is a "set it and leave it alone camp" and one that uses a tuner as I believe, it best, which is to tune with and maintain peak tune with. But again, if you don't establish increment values to begin with, well...you are probably better off to leave it alone and just test ammo to find lots that shoot well at a given setting.

I've never understood the Hopewell method's popularity. It's just picking a full revolution at a time as a beginning increment. Thing is, WHY? Why that amount? What about any other tuner design, thread pitch, weight, location...lots of variables to that and NOBODY actually factored everything involved into the tuner design nor increment value when they made a tuner. Can't be done that way on the front end. You have to build the tuner and test, then establish mark increments that work with the design.

It's really not hard and yes, there's more than one way to tune. The method I use works for me, rf and cf, and is just a much more methodical approach that allows me to use a tuner to actually TUNE with.

 

[gunsandgunsmithing]

If positive compensation works so that faster and slower rounds converge at a single POI at 50 that means their trajectories intersect at that distance. In other words, faster and slower rounds must have different trajectories from muzzle to get to the same POI at 50.

It would seem to follow that rounds with different MV's yet the same POI at 50 must begin to diverge once past 50.


_________________________

On a more practical level, regardless of how tuners actually work shooters wishing to use tuners should have as realistic appreciation as possible of what tuners can achieve.

When perfectly set how much improvement can tuners be expected to give at 50? Will they "shrink" groups by 10%? 20%?

That depends. Perfect tune is just that and can not be improved upon..tuner or not or by other methods. But what are the odds that you buy a lot of ammo and it be the best the gun has to offer right out of the gate? It does happen but tuners typically do reduce group size because they are a tool that lets you optimize where the bbl is pointing when the bullet reaches the muzzle...err, tune the rifle to the ammo.

BTW, tuners do NOT create PC. It's there before tuners were ever dreamt of. But they do allow us to manipulate phase time, timing bullet exit and muzzle position for it. Very, very much like handloading in cf.

There's nothing magical or mystical about a rf vs a cf. Both have what's called a cantilevered beam...a bbl, that we manipulate with the tuner to optimize bbl position at bullet exit. Biggest difference is the bullet is in the bbl 3x as long as a rf.

 

[PNW Skipper]

Maybe I misunderstood what Positive Compensation means as it relates to rimfire. but if you truly achieve PC why would distance changes affect it?
my understanding is that PC will flat line slow and fast rounds so they intersect and have same POI meaning if I shot 10 lots of various speeds, they all should have same POI.
therefore, distance should only affect POA to POI meaning adjusting POA is all that would be needed.
PC should not

Maybe I misunderstood what Positive Compensation means as it relates to rimfire. but if you truly achieve PC why would distance changes affect it?
my understanding is that PC will flat line slow and fast rounds so they intersect and have same POI meaning if I shot 10 lots of various speeds, they all should have same POI.
therefore, distance should only affect POA to POI meaning adjusting POA is all that would be needed.
PC should not have changed.

Lee

Lee,

If you go into a ballistics calculator and graph thr path for rounds that have different speeds, but are zeroed for 50 yards, you find that beyond that common point the paths diverge. At 100 yards, for about a 175 fps difference (Lapua OSP vs Biathlon), there is roughly 5" vertical difference in the path. So the angular difference for that velocity difference to coincide at 100 yards is necessarily greater than at 50 yards.

 

[Hi-NV Shooter]

I'm wondering how many setup their tuner to shoot good at 50 yards, and it also shoots pretty good at 100 yards....and just accept that as is without trying to tweak the tuner to make it shoot better at 100 yards instead of just pretty good?

I would think if they intended to shoot at 100 why would they tune at 50 first that should be the question
I never intended to shoot at 100 first it was secondary it was always at 50 first
I started to shoot at 100 only for curiosity and learned ammo performance was important. This is where a lot that you know shoots at 100 in this case 100m helps to understand what is going on with your tune
Being able to compare other lots will quickly show if your tune is good

Lee

 

[MarkS]

This is for rimfire, not cf..fwiw. There are small differences between them but nothing huge.

I'm gonna keep this very short. Got a dying family member and no time to debate but I'll just say, why not simply test a few marks on both sides of a sweet spot at both distances. IME, the difference between 50 and 100 is not a lot but with some guns and some ammo, 2 marks on my tuner is about right to correct it. (the harrells is pretty similar IME) And what you will normally see, that isn't wind induced, is vertical in those 2 marks difference. So, if it'd dead nutz in tune at 50 but a bit of vertical at 100, move it 2 marks either way and try it. You'll quickly learn which way is right on your gun. Same goes for learning the next few groups in 2 mark intervals. Just try it but go no more than 2 marks at a time for about 15 groups of five. Ideally, do all groups on the same horizontal plane, so vertical poi changes are clearer, Some guns show this change clearly while some do not, especially rimfire. I'll post a pic of the target I use in a minute. It really shows me everything I look for. Maybe most importantly, it shows the value of each incremental change and how those changes show up on the target. When done, go back and test 1 mark for a few groups around the sweet spots that you find in that 15 group test. You may very well find improvement with just 1 mark.

I am a long range rimfire steel shooter. shooting steel out to 400yds. I use EC V2 tuners. I start at 50yds shooting 3 shot groups and move 5 marks. I take the best of best groups at to 200yds. I do the same as you are saying, moving 2 marks at a time each way. I am looking for vertical only. not worring about the wind. On a very good no wind day I tuned at 400yds, moving only moving a few marks.

 

[Hi-NV Shooter]

Lee,

If you go into a ballistics calculator and graph thr path for rounds that have different speeds, but are zeroed for 50 yards, you find that beyond that common point the paths diverge. At 100 yards, for about a 175 fps difference (Lapua OSP vs Biathlon), there is roughly 5" vertical difference in the path. So the angular difference for that velocity difference to coincide at 100 yards is necessarily greater than at 50 yards.

This why PC is not possible partial perhaps but not 100% PC

Lee

 

[whiddengunworks]

grauhanen, I have reasonably good data on 2 of my own rifles. The difference between the best tune and the worst tune was 16% and 30% smaller on group diameter at 50M.​

Comparing the best tune vs. the average, the difference was 5% and 19%.

I still feel like our data is very limited at this point. It will be interesting to continue our learning.