Help Me Design a Tuner Test

[JimSC]

No offense Lee but I look at tuning just like I look at loading for OBT but instead of adjusting the bullet speed with changing the amount of powder or bullet jump I adjust the harmonics of the barrel by moving the tuner slightly. What I need to do now is sontinue with the experiment seeing exactly how much the FPS changes over a large temp spread.

On the Vudoo I originally set the tuiner at 1round 45 -50 F, at 90F I have had to move the tuner exactly two clicks to accomidate different ammos and the incrtease in temp. I t was't that the rifle starting shooting bad, just a slight adjustment of made it shoot better when the temps started to rise and I am guessing I wil move it back when the temps lower.

I set aside a brick of ammo for the long running test and made a nice spreadsheet last eve. I plan on shooting a 90F baseline tommorroe then repeat several more times as the temps drop.

Not that I doubt you buit it is something to do that keeps me out of the bars and off the streets

 

[Hi-NV Shooter]

No offense Lee but I look at tuning just like I look at loading for OBT but instead of adjusting the bullet speed with changing the amount of powder or bullet jump I adjust the harmonics of the barrel by moving the tuner slightly. What I need to do now is sontinue with the experiment seeing exactly how much the FPS changes over a large temp spread.

On the Vudoo I originally set the tuiner at 1round 45 -50 F, at 90F I have had to move the tuner exactly two clicks to accomidate different ammos and the incrtease in temp. I t was't that the rifle starting shooting bad, just a slight adjustment of made it shoot better when the temps started to rise and I am guessing I wil move it back when the temps lower.

I set aside a brick of ammo for the long running test and made a nice spreadsheet last eve. I plan on shooting a 90F baseline tommorroe then repeat several more times as the temps drop.

Not that I doubt you buit it is something to do that keeps me out of the bars and off the streets

Jim,

I take no offense, and I hope you don't either. what I wrote is what I have seen. and I am not saying those who make slight adjustments are wrong. I am stating why there is a need too, the last thing a competitive shooter needs are doubt on how their rifle is shooting.

This is supposed to be a fun thing we do and if it keeps us out of trouble that's even better.

Lee

 

[TRSR8]

Jim,

IMO there are two categories of rifles that use tuners. First is a rifle that is made to shoot meaning it can shoot really good but can go out of tune and needs what you are saying a click or two to get back in tune using the same ammo from previous shooting. in most case it is rather picky on finding good lots it will shoot.
Then there are rifles that are truly tuned ones that do not go out of tune no matter what. it will shoot the same with known good ammo every time. a rifle that is also truly tuned will also be able to find ammo that will be that much better than the lots before. it is not picky on ammo lots.
one thing that is also important to obtain a rifle that can be truly tuned is the barrel. a barrel that is really good will be easier to tune. good ammo will only shoot as good as the barrel is capable same holds true with tuning. a really good barrel and really good ammo will only shoot as good as the tune will allow them too.

if you need to adjust using the same lot of ammo it really wasn't tuned. Think about that for perspective on tuning

Lee

Truer words were never spoken, why, no doubt, often, the best guns built by the best smiths wearing better barrels, get tuned properly and permanently. Should you be fortunate enough to have one or two, you don’t need to spend a year finding a tune.

 

[grauhanen]

IME, cf far exceeds rf accuracy in moa so I don't think it's about jacketed or not., but more, ammo quality in general.

Jacketed centerfire bullets can be manufactured to have centers of gravity more perfect than those of soft lead .22LR bullets. As long as soft lead bullets have variation in centers of gravity this shortcoming results in a distinct disadvantage for .22LR accuracy in MOA.

I'll tell you the same as I said before...If you want data that you trust, there is nothing but air and opportunity between you and having it.

This seems like a safe response if there is little or no evidence published in print or online to support the idea that with .22LR rounds with the same MV can have different "pressure curves" which in turn causes different trajectories.

 

[gunsandgunsmithing]

Jacketed centerfire bullets can be manufactured to have centers of gravity more perfect than those of soft lead .22LR bullets. As long as soft lead bullets have variation in centers of gravity this shortcoming results in a distinct disadvantage for .22LR accuracy in MOA.

This seems like a safe response if there is little or no evidence published in print or online to support the idea that with .22LR rounds with the same MV can have different "pressure curves" which in turn causes different trajectories.

It's out there if you look for it enough. There may be a cached version of the RSI Laboratory site but I do think they closed shop. Hopefully not. Their Pressure Trace system used simple strain gauges to measure the stretch of the bbl under pressure. Others on here are familiar. I'm not making anything I say up. The safe thing is to test yourself. It just is. I could post tons of stuff but some will still question every detail. Just do it, post it...and you will see but most importantly, you will know what you learned and under what circumstances. Testing is how we know stuff! It's fun! Enjoy!

 

[WyleWD]

What I see in your target is the same sine wave as this from gunsandgunsmithing:
View attachment 1581231

And it still seems to me that the best place to be with a tuner is at the node of the wave.

This is the test method I used when testing for tuner settings on a 40x with a fluted Shilen 22RF. This was the first time I ever shot a rifle with a tuner in my life. It requires some serious thought, time, several types of ammo, wind conditions/ flag reading skills and making sure you have your bench manners wired up and consistent. I'm pretty sure we've seen some shooters that need WAY more than a tuner to improve their shooting. JME

I've tried 6 different types of ammo with this test. And it works like a charm. Yielded some great groups in the end and some good trigger time. Also showed me that some ammo will have fliers no matter what. The bonus was that 3 types of ammo were within +/- 3 small adjustments and another was very good at -5 small adjustments. Keep good notes on the target and keep the target for future reference. JME.WD

 

[CharlieNC]

A tuner cannot compensate for every conceivable possibility that can be imagined, which is why good ammo must be utilized as well. Years ago Kolbe published an excellent article, Good Vibrations, utilizing an instrumented rimfire barrel to demonstrate positive compensation improved accuracy when a tuner was attached. The muzzle trace shows the effect of modifying exit timing during vibration(s). Well worth the read for anyone who wants to begin to understand what's going on.

 

[gunsandgunsmithing]

A tuner cannot compensate for every conceivable possibility that can be imagined, which is why good ammo must be utilized as well. Years ago Kolbe published an excellent article, Good Vibrations, utilizing an instrumented rimfire barrel to demonstrate positive compensation improved accuracy when a tuner was attached. The muzzle trace shows the effect of modifying exit timing during vibration(s). Well worth the read for anyone who wants to begin to understand what's going on.

Using barrel vibrations to tune a barrel

 

[TRSR8]

The answer is there Tim. Again, please pay attention rather than trying to create a point of contention that isn't there. We actually agree! You said yourself, that the tuner gets moved very little. THAT'S WHAT I'VE BEEN PREACHING, TOO!
You're never far away so moving in full revolutions is where people get screwed up and lost. Hence, they end up leaving them at a spot and living with the consequences, not realizing that it may do a bit better with a SMALL tweak of the tuner. This isn't hard at all and it's just a tuning method that is, wait for it...METHODICAL!
If you have a different way that works, stay with it. Again, said the same thing for 15 plus years now. Do what works for you but testing is how we know stuff. Not what he said, she said internet babble. Test man!

You missed the main point.
Reading some of these guys efforts, lots of them start with a tuner all in or all out and given a few click intervals waste time/ ammo / effort getting anywhere.
The established set points used by several allow far less of all to finish.
Also, FWIW, the best barrels getting fit, according to a couple world class smiths, exhibit little or no change with a click or two once you’re at a workable tune point although personally, I see nothing wrong with trying and, yes, I’ve tested this extensively……end up right back where Eck set them years ago. shot 250’s then, now, hot, cold, everywhere in between without the need for ammo lot switching.
Lots of guys seem not to realize there are plenty of barrels out there where this is not possible and those barrels will frustrate the hell out of you and far fewer can actually identify this.

 

[CharlieNC]

You missed the main point.
Reading some of these guys efforts, lots of them start with a tuner all in or all out and given a few click intervals waste time/ ammo / effort getting anywhere.
The established set points used by several allow far less of all to finish.
Also, FWIW, the best barrels getting fit, according to a couple world class smiths, exhibit little or no change with a click or two once you’re at a workable tune point although personally, I see nothing wrong with trying and, yes, I’ve tested this extensively……end up right back where Eck set them years ago. shot 250’s then, now, hot, cold, everywhere in between without the need for ammo lot switching.
Lots of guys seem not to realize there are plenty of barrels out there where this is not possible and those barrels will frustrate the hell out of you and far fewer can actually identify this.

So it depends on barrel length and contour, and how that interacts with tuner weight and graduations. What's new to report?

 

[JimSC]

I spent most of the day at the range, it was hot 85-90 F and 70% humidity. Mild 4 -7 mph winds. I played with my CZ 457 Varmint waiting on the temps to climb, and did some ammo testing. Afterward I pulled out the Vudoo and established baseline velocities for bare muzzle, bare tuner, tuner with the noodle slide ring in various posiotions at 90F usin a lot of SK SA that shoots good, not great but good enough to do velocity checks with. Twnety five rounds had an ES of 36 and a SD of 9.6

I had finished and was waiting on a cold range and saw a box or RWS target that was most empty from the CZ testing and decided to finish off that box in the Vudoo while waiting. First two five round groups had vertical stringing so I brought the tuner down 2 clicks and the third ( 5 round) and fourth (7 round) groups.

People can can set and forget all they want but sometimes a click can make a difference. Centerfire benchrest and F class shooters have know that for years The two rounds on the right in 4th group were pure wind but those 2 clicks made that vertical go away.

 

[gunsandgunsmithing]

I spent most of the day at the range, it was hot 85-90 F and 70% humidity. Mild 4 -7 mph winds. I played with my CZ 457 Varmint waiting on the temps to climb, and did some ammo testing. Afterward I pulled out the Vudoo and established baseline velocities for bare muzzle, bare tuner, tuner with the noodle slide ring in various posiotions at 90F usin a lot of SK SA that shoots good, not great but good enough to do velocity checks with. Twnety five rounds had an ES of 36 and a SD of 9.6

I had finished and was waiting on a cold range and saw a box or RWS target that was most empty and decided to empty that box in the Vudoo while waiting. First two five round groups had vertical stringing so I brought the tuner down 2 clicks and the third ( 5 round) and fourth (7 round) groups.

People can can set and forget all they want but sometimes a click can make a difference. Centerfire benchrest and F class shooters have know that for years The two rounds on the right in 4th group were pure wind but 2 clicks made that vertical go away.

View attachment 1582454

That'll never work Jim! Lol! It'll shoot small but it's not tuned. Lol!
To a degree...I actually agree with that tongue in cheek comment though. You can clearly see the poi is lower on the latter groups. If you're running my or a Harrel's, I'd love it if you went 18 marks in the same direction as your last adjustment. I'd bet the poi moves up and you're within 2 marks of dotting up again. Is it possible for you to do this for me? If not today, conditions might be different but not likely enough to change the outcome a lot. Here, we had a huge difference in conditions overnight though..fwiw. Much cooler today.

Ideal would be three 5 shot groups at 16,18 and 20 away from where it dotted up in your pic

 

[JimSC]

I had not seen that, thanks for poitning it out, here is a overlay of those 12 shots, almost .5 vertically. I will have to play with that ammo, I have 3 bricks of it on the shelf and my CZ's hate it. Yep I will head to the range again tommorrow if the wife will let me out of the house. I will start where it is at and go down in 2 click incs

edit cleared it with the wife and checked the weather, tomorrow afternoon will be almost the same, a couple of degrees cooler and a little less wind

 

[gunsandgunsmithing]

I had not seen that, thanks for poitning it out, here is a overlay of those 12 shots, almost .5 vertically. I will have to play with that ammo, I have 3 bricks of it on the shelf and my CZ's hate it. Yep I will head to the range again tommorrow if the wife will let me out of the house. I will start where it is at and go down in 2 click incs

edit cleared it with the wife and checked the weather, tomorrow afternoon will be almost the same, a couple of degrees cooler and a little less wind


View attachment 1582469View attachment 1582469

Vertical is typically just 2 marks from dotting up. Try it before starting. Tune may come to you regardless of temp but won't knw til ya try.. Either way, you'll be really close...a couple of marks either way. We haven't covered how to know which way here yet but my test tells ya!

 

[Hi-NV Shooter]

I spent most of the day at the range, it was hot 85-90 F and 70% humidity. Mild 4 -7 mph winds. I played with my CZ 457 Varmint waiting on the temps to climb, and did some ammo testing. Afterward I pulled out the Vudoo and established baseline velocities for bare muzzle, bare tuner, tuner with the noodle slide ring in various posiotions at 90F usin a lot of SK SA that shoots good, not great but good enough to do velocity checks with. Twnety five rounds had an ES of 36 and a SD of 9.6

I had finished and was waiting on a cold range and saw a box or RWS target that was most empty from the CZ testing and decided to finish off that box in the Vudoo while waiting. First two five round groups had vertical stringing so I brought the tuner down 2 clicks and the third ( 5 round) and fourth (7 round) groups.

People can can set and forget all they want but sometimes a click can make a difference. Centerfire benchrest and F class shooters have know that for years The two rounds on the right in 4th group were pure wind but those 2 clicks made that vertical go away.

View attachment 1582454

Jim,

Do you compete in RFBR?
Also, unless those CFBR and F-class shooters are using factory loaded ammo and using a tuner like we do in RFBR there is no correlation to RFBR.
FWIW it is not just about the smallest groups it is about consistency at least in RFBR if you just use the smallest groups, you can get and not the most consistent you will always be making those little adjustments.

And if you use just one very small group as the standard you are even farther away than you think. show me 5 tiny groups like your example in a row 25 shots total then I may even make adjustments myself!

Lee

 

[JimSC]

Almost identical conditions as yesterday bvut a bit windy. 3 - 7 MPH. I waited for slack tails on the tuner workup but shaded my shots on the practice target. Both the points I dropped were almost exactly at the POA but I missed the wind drop off. Low X count but I am happy with it considering it was with $8 a box ammo shot by a rookie. On ARA unlimited would have probably been a 2000 maybe 2100 depending on how the plug treated me





edit just did a composite in OnTarget and for the twenty five shots it showed vertical of .321 inches and a CEP 95% of .297 inches. Width was .562 CTC so I still have a lot of room for improvement for my horizontals but I don't think I can get mid price ammo to shoot any better. Only thing that can help this tune is lots of trigertime in windy conditions. Next I need to shoot the same target with CX, and a couple of flavors of SK see if the tune holds or needs a click or twoi.