Help Me Design a Tuner Test

[gunsandgunsmithing]

Yes, I mean node.

I say that because as @gunsandgunsmithing says here, the tuners we use are mounted in front of the muzzle; meaning the bullet is released before it exits the tuner (in my case, I use a tuner-break). The tuner has added length to the cantilever, changing the harmonics and maybe even the harmonic mode and where the node is. My thinking is that the change in the harmonic that the tuner does moves the node towards the muzzle where the bullet is released, which could not happen without the lengthening of the cantilever (barrel + tuner). And can be further moved according the the tuner adjustments. The bullet release point doesn't change (barrel length stays the same) with the lengthening of the cantilever by the tuner, the location of the node does. Anyhow, this is my current thinking.

Example of where the node is for Mode 2 of this cantilever and its frequency:
View attachment 1581589

Different modes shapes for the different frequencies:
View attachment 1581588

Just because you are currently using mostly tuners that extend beyond the muzzle, or have no experience with other designs, does not change the fact that behind the muzzle tuners also work. How do you explain that? I'm not advocating them but I've certainly used and tested them. A couple of examples are the Gene Beggs and the Jim Borden tuners...fwiw.
Frankly, it seems to me that you put more value in you your own theory than my actual testing. That's fine but it doesn't make you right.

I believe the subject was developing a tuner test. Let's get back to the ops topic.

 

[grauhanen]

The other thing and it's big, the pressure curve can change while the final muzzle velocity stays the same. Yes, less powder and pretty awesome case efficiency of a 22lr does make changes smaller than in cf. The biggest variable is the one that is a chemical reaction. That's smokeless powder turning from a solid to a gas.

This seems very important for .22LR. If it's "big" as you say it has the potential to upend performance. It seems unpredictable and impossible to detect by the shooter. It may cause rounds with the same MV to behave differently, to have different trajectories.

If two .22LR rounds with the same MV have different "pressure curves" this suggests that in the same bore they don't get from 0 fps to their identical MV the same way. In other words, they took different amounts of time to do so or they sped up/slowed down differently in the same bore while exiting with the same velocity.

How can any shooter know when rounds from the same lot having the same MV didn't have the same pressure curve?

Would two such rounds with the same MV have different trajectories in an untuned barrel? Would they have different trajectories in a tuned barrel?

 

[gunsandgunsmithing]

This seems very important for .22LR. If it's "big" as you say it has the potential to upend performance. It seems unpredictable and impossible to detect by the shooter. It may cause rounds with the same MV to behave differently, to have different trajectories.

If two .22LR rounds with the same MV have different "pressure curves" this suggests that in the same bore they don't get from 0 fps to their identical MV the same way. In other words, they took different amounts of time to do so or they sped up/slowed down differently in the same bore while exiting with the same velocity.

How can any shooter know when rounds from the same lot having the same MV didn't have the same pressure curve?

Would two such rounds with the same MV have different trajectories in an untuned barrel? Would they have different trajectories in a tuned barrel?

No, velocity sets trajectory. Of course bc wind etc but in this context, no.

Now launch angle may well be different. That's relative to tune though and why poi changes with tuner movements.

 

[Hi-NV Shooter]

at least from 50F to 90F using half a dozen flavors of ammo I have not seen a need to change tuner setting more than three or four clicks to tune. The other day was about 90F and the Vudoo was shooting set at 395 and 2nd slider hole with SK gray box

I am thinking the need to make an adjustment with temperature swings is more on the ammo than the tune.
if you have the right setting for that rifle /barrel combination with known good shooting ammo no changes should be needed.
I shoot in temperatures of mid to low 30's to highs in the 100+ with the same lots I only see a slightly higher POI in the higher temperatures. my scores are pretty consistent. but i will say this I like to tune in lower temperatures. the reason being when I find a setting that will give me the highest bullet exit with various lots it will in most cases be the setting I am after. from what I have seen cooler temperature give more stable bullet exit timing. whereas higher seems to be much more inconsistent.

Lee

 

[Ccrider]

1. I'll start with the current setting and shoot 10 rounds. 2. I'll move the tuner to current +1 and current + 2 and shoot 10 rounds at each place. 3. I'll move the tuner to current -1 and current -2 and shoot 10 rounds at each place. This will give me 5 groups of 10 shots each. I'll repeat the test 4 times and do this in the same order.

Presumably, current setting is where you have determined that the rifle shoots best?

If not, I would say shoot 0-5 in progression. If so, shoot -2, -1, current setting, +2, +1. The targets and tuner impact should be easier to read that way.

 

[grauhanen]

No, velocity sets trajectory. Of course bc wind etc but in this context, no.

Now launch angle may well be different. That's relative to tune though and why poi changes with tuner movements.

Velocity and launch angle indeed play major roles in setting trajectory.

Assuming that it's generally accepted that .22LR rounds with the same MV can often have different pressure curves, such rounds with the same MV will have different launch angles and hence different trajectories. (With regard to .22LR, this doesn't seem to get a lot of attention. Is there reliable information specifically on .22LR either in print or online?)

How can a shooter know that same rounds with the same MV have different pressure curves and hence different trajectories? Only by POI?

Perhaps there is something else (air movement etc. excluded, of course) that will also help explain why two .22LR rounds with the same MV from the same barrel can have different trajectories.

Without involving different pressure curves (or wind), when .22LR bullets have nearly perfect centers of gravity, rounds will have predictable trajectories based on their MVs and launch angles.

Unlike jacketed centerfire bullets, soft lead projectiles such as .22LR bullets (and airgun pellets) are difficult to manufacture with nearly perfect centers of gravity. Will differences in centers of gravity (bullet imbalances) between .22LR rounds contribute to different trajectories for rounds with the same MV?

It seems unlikely that a tuner can "fix" trajectories created by bullet imbalance.

 

[JimSC]

It seems unlikely that a tuner can "fix" trajectories created by bullet imbalance.

in laymans terms, a tuner won't fix flyers. It can make ok ammo shoot good, good ammo shoot great and great ammo shoot amazing but the only thing that can fix flers is quality control and good bench habits

 

[gunsandgunsmithing]

Velocity and launch angle indeed play major roles in setting trajectory.

Assuming that it's generally accepted that .22LR rounds with the same MV can often have different pressure curves, such rounds with the same MV will have different launch angles and hence different trajectories. (With regard to .22LR, this doesn't seem to get a lot of attention. Is there reliable information specifically on .22LR either in print or online?)

How can a shooter know that same rounds with the same MV have different pressure curves and hence different trajectories? Only by POI?

Perhaps there is something else (air movement etc. excluded, of course) that will also help explain why two .22LR rounds with the same MV from the same barrel can have different trajectories.

Without involving different pressure curves (or wind), when .22LR bullets have nearly perfect centers of gravity, rounds will have predictable trajectories based on their MVs and launch angles.

Unlike jacketed centerfire bullets, soft lead projectiles such as .22LR bullets (and airgun pellets) are difficult to manufacture with nearly perfect centers of gravity. Will differences in centers of gravity (bullet imbalances) between .22LR rounds contribute to different trajectories for rounds with the same MV?

It seems unlikely that a tuner can "fix" trajectories created by bullet imbalance.

I'm not sure I follow your last couple of statements clearly enough.

In regard to pressure curves, I used a pressure trace system for a few years to grap this exact sort of thing for a few years...then apparently lightning took it out and I never bothered to buy another one, but it was handy. Rsi was the company and they seem to be gone now...fwiw. They were not intended for absolute pressure measurements but we're fantastic for just this...comparative measurement, and could graph out the whole pressure curve for you. Handy in this regard, at least. Without a similar means, I'm not sure how one would graph and measure these things economically. We had this ability during vibration analysis but some or most of the equipment was already owned by the university...in round one of testing.

 

[gunsandgunsmithing]

in laymans terms, a tuner won't fix flyers. It can make ok ammo shoot good, good ammo shoot great and great ammo shoot amazing but the only thing that can fix flers is quality control and good bench habits

It's about tune. Whateverv potential the ammo has in that gun, a tuner can get but the process has to be more methodical than much of what I read on shooting forums to provide reliable data.

 

[TRSR8]

It's about tune. Whateverv potential the ammo has in that gun, a tuner can get but the process has to be more methodical than much of what I read on shooting forums to provide reliable data.

Wonder why some of the builders of the absolute best performing, world record rifles go with their tuners set, pretty much , at an established number that then gets moved little, if any.
Had a barrel recently fit by a guy that has won about everything winnable for decades……same thing.
Results, Mikey…..all about results.

 

[gunsandgunsmithing]

Wonder why some of the builders of the absolute best performing, world record rifles go with their tuners set, pretty much , at an established number that then gets moved little, if any.
Had a barrel recently fit by a guy that has won about everything winnable for decades……same thing.
Results, Mikey…..all about results.

I've been preaching "close or very close" for about 15 years. You're just not paying attention. All you bring to any discussion is what somebody else has done because you don't test and learn for yourself. You are the internet's version of Mr Ed. Just bring something of value or stfu. You follow me around to turn threads into shit shows and it should be stopped. That's JMHO but you do this to others on every forum you belong to.

 

[grauhanen]

I'm not sure I follow your last couple of statements clearly enough.

I'll try to be more succinct.

Center of gravity variation or imbalance in .22LR bullets causes unpredictable trajectories.
______________________

Perhaps it's more well-known with centerfire, but there seems to be little information available about .22LR pressure curve curve differences that may cause trajectory unpredictability. Further reliable information about this with regard to .22LR either in print or online would be most welcome.

With .22LR perhaps Cg variation is more common than pressure curve variations.

 

[gunsandgunsmithing]

I'll try to be more succinct.

Center of gravity variation or imbalance in .22LR bullets causes unpredictable trajectories.
______________________

Perhaps it's more well-known with centerfire, but there seems to be little information available about .22LR pressure curve curve differences that may cause trajectory unpredictability. Further reliable information about this with regard to .22LR either in print or online would be most welcome.

With .22LR perhaps Cg variation is more common than pressure curve variations.

CG is external ballistics and at least mostly has nothing to do with tuners or likely even tune without one at all. 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.

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.

Hey, at least we haven't had anyone pipe in and claim a rf is different due to magical and mystical things that only art can fix...yet.

 

[TRSR8]

I've been preaching "close or very close" for about 15 years. You're just not paying attention. All you bring to any discussion is what somebody else has done because you don't test and learn for yourself. You are the internet's version of Mr Ed. Just bring something of value or stfu. You follow me around to turn threads into shit shows and it should be stopped. That's JMHO but you do this to others on every forum you belong to.

Notice, after the sporty retort, no answer to the above point. Why is that Mike? Please enlighten us.

 

[USMCDOC]

 

[gunsandgunsmithing]

Notice, after the sporty retort, no answer to the above point. Why is that Mike? Please enlighten us.

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!

 

[seymour fish]

Wonder why some of the builders of the absolute best performing, world record rifles go with their tuners set, pretty much , at an established number that then gets moved little, if any.
Had a barrel recently fit by a guy that has won about everything winnable for decades……same thing.
Results, Mikey…..all about results.

Tim, your “I know a guy” appeal to authority leaves us begging for more of your tricks.

 

[JimSC]

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!

best advice I have ever read on tuning right there. If you are seening a bit more vertical while using a known good ammo try moving the tuner 1 or 2 clicks can make the difference between 50's and 100's. If you have a adjustable noodle just moving the slider up or down a hole also can tighten a group right up

 

[TRSR8]

Tim, your “I know a guy” appeal to authority leaves us begging for more of your tricks.

Authority??? Must be nice hanging out in the shallow end of the thought pool.

 

[Hi-NV Shooter]

best advice I have ever read on tuning right there. If you are seening a bit more vertical while using a known good ammo try moving the tuner 1 or 2 clicks can make the difference between 50's and 100's. If you have a adjustable noodle just moving the slider up or down a hole also can tighten a group right up

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