Ultimately, you have to do the testing for yourself. When I first started testing tuners, it was 3 commercially available models. The instructions that cam with each were vastly different from one another. But, following each, you could see group shape and size change without question. The problem came with, "where do I go from here". I was not satisfied with the instructions from any of them but I could see that they changed tune. So, I went DEEP into the tuner rabbit hole., all the way to vibration analysis testing...and learned a lot along the way.
If you notice, I don't go into telling specific instructions on how to use anyone's tuner but my own, for which, I go into great detail when you order from me. This is why I only do tuner orders by phone.
There are differences in how to adjust different tuners and to a smaller degree, even on which barrel contour. And RF is another rabbit hole, in itself.
Ultimately, I believe we are headed to the point where a tuner is just as much a part of a new build as a stock, barrel and trigger are because tuners flat work and are an invaluable tool to maintain tune with. They are golden! The trick is harnessing what they do, for your benefit. I PROMISE this much...if you move a tuner randomly, you WILL get random results...Doesn't matter which one you use.
So, the key is to quantify the value on target of each mark on your tuner. It's a pretty simple process but it's not the same for every tuner. I will say that, by far the most common mistake is moving them too far at a time and that with any tuner I've ever seen, the length of the threads has absolutely ZERO to do with how far it is between sweet spots or how it's adjusted...ZERO! Don't assume an inch or three of threads has anything to do with how far it is between sweet spots. I won't use the term node, because technically speaking, that's exactly the worst place to be with a tuner setting. There are nodes and there are anti-nodes. We want to tune to an anti-node, regardless of accepted terminology contrary to this. It's mostly irrelevant, as long as we understand that we want the bullet to exit while the barrel is moving least, regardless of what we call that spot.
Lets move on.. but I'll keep my info relative to my tuner from this point forward. You'll have to test other makes on your own but there'll be a lot of relative info to all makes of tuners going forward. Some of what I'll say is a generalization to keep it as short and as understandable as I can make it but to those wanting to split hairs, call me and we can discuss it further. I find that keeping things as simple and understandable as possible, to be more beneficial to most all of us than splitting hairs about technical jargon. As long as we're on the same page, the rest is easy, but I'm happy to clarify things as best I can in a personal phone conversation. Point being, I want to get the gist of what tuners do, across to as many as possible without getting caught up in details of things like terminology..as long as we can all understand it to our benefit without getting too long and boring, for naught. Remember this important point, if someone understands something well, they can convey it to most anyone without talking in technical terms that no one really knows or cares about.
Here we go...
I have a simple test procedure for establishing tuner setting that will show two sweet spots in less than a revolution of my tuner.
Everything matters! Doesn't matter at all how far you compete at for this test!!! It's all about learning what the tuner does without having 1000 yards of wind between you and the target to skew the test.
I start by taking a piece of target paper, or better yet, a piece of cardboard about 18" wide and maybe 6 inches tall. I draw a single horizontal line all the way across it with 15 vertical intersecting lines about an inch tall. We're gonna use the intersection of the lines as aiming points. The importance of it all being on one horizontal plane will be more obvious when you shoot the test, but in a nutshell, it'll show small vertical displacement of the groups and sweet spots clearly.
If we have a known good load and tuner setting, it's important to intentionally take the gun out of tune by moving the tuner INWARD by two marks. The importance is that you want repeatable results for a couple of marks on BOTH sides of in tune.
Now, we're gonna shoot 15
three shot groups, moving my tuner by one mark or number value at a time(0-1, 1-2,2-3, etc). Now this is for centerfire! I'll get to rimfire later but they are pretty similar.
We're gonna see three important things happen!
Within 15 groups at 1 mark intervals, you'll see two sweet spots. One will print slightly higher than the other one. I use the one that prints highest BECAUSE, it will hold tune better in lieu of small velocity variations. This is what you may have read about...positive compensation. It's not unusual to see a smaller group at the bottom of the swing, on a single 3 shot group basis. I happens a lot but the top is where tune will hold best, IME.
Alright, now we've already established two things. We've established how far it is between completely in tune and completely out of tune as well as top of the barrel swing and bottom of the barrel swing.(imagine a simple sine wave).
The third and most important thing you'll see is the group size and shape at each setting between in tune, completely out of tune..and back into tune.
Now, lets back up for a minute...
First, we want the sweet spot at the top...
check
Second, we want to know how far from the top of the barrel swing to the worst setting(node or scatter node) It's amazingly predictable how far that is as well as group shapes along the way!!!!
Barrel stiffness is the primary factor in how far it is between completely in tune and completely out!! Lots of people assume that a fatter barrel is more stiff than a skinnier one. This is true
PER INCH, but not necessarily so, if we're comparing a say..24" hv to a 30" 1.250 staight!
What I've seen in use is that it is very typically about 4 marks from in tune to completely out on a typical 23-24" short range barrel and 5 marks on a 28-32in long range barrel!!! That's important but is a small difference between what a lot of people think should be very different. It's NOT! Keep in mind, this comes from testing on target as well as watching the difference on an oscilloscope, as well as several hundred(maybe more) barrels in use today.
What should you expect?...about 4 marks between completely in tune to completely out of tune on a typical short range centerfire br rifle and abou 5 marks on a typical cf long range rifle.
It's remarkably predictable! To the point that I've been able to diagnose gun issues, like bedding or loose screws, based on group shape!!
Very, very typical scenario is this...
Dead nuts in tune hopefully just dots up at 100
1 mark out is straight vertical..about a bullet hole, or a figure 8
2 marks is stairsteps up and to the right. Lets stop there for a minute!
There is no wind condition that gives stairsteps up and to the right, from a rh twist barrel!!! On top of that, I've tested over a 45° temp swings, repeatedly...All else equal(same load and gun), I've never been more than about 2 marks away from in tune!!!
Read THAT again!!
So, while you might be as far as 4 or 5 marks away, at most...I've never been more than two marks away from in tune, due to condition related changes!!!
IOW, the tuner can take you more out of tune than any condition related change can!! And..as a rule...if temps go up, move the tuner in(shorter), as temps go down, move the tuner out(longer).
Down and out!!
I'm probably forgetting something but this is already long. I've been aiming to put this in print for a long time now, but it covers so much ground and takes some time.
Again, this is for MY tuner, but others are remarkably similar. Just be very methodical with whatever tuner you have!!! And be disciplined!!! It's easy to blame the tuner when you are pulling trigger at the wrong time(refer back to my point about a rh wind) because it's so easy to blame and wrongly adjust that thing on the end of the barrel. Rule of thumb...Don't move the tuner unless you'd get up and change your load, as you're essentially doing the same thing!!
Bottom line is there should be a rhyme and a reason to why and how far you move any tuner. If you're guessing, you haven't done your homework.
Thanks for your patience with this long post but I hope it's helpful to anyone wanting to try one. It's really the simplest tuning method I've ever seen. It's just different.
Oh...one more thing. Remember I said 1 mark away is straight vertical? Long range guys tend to run backward from vertical. Work it out of the load first! When you have a tuner and you get vertical, you're CLOSE! You're likely one mark away from in tune!!!!
I hope other tuner makers off this same kind of assistance with their products. IME, few if any do.
View attachment 1277969