I think you've concluded the correct answer...it's not a winning rifle. Sure, you could keep trying stuff like different powders, fat bullets, etc... but you would be ahead if you just gave up on it.
Just an opinion as you're smarter about this stuff than I am...
By the way - have you tried fat bullets?
Let me explain. Good question; I'll try to explain. Huh? Yep, it's true! Sure, you do not yet know whether you are tuned to the top or the bottom but who cares; conditions aren't going to change during the 7 minutes you have to shoot five record shots. If the tune proves to be very sensitive we can easily reverse it and jump to the top stop by increasing the load by 1.2 grains. So let's try some examples: Let's say 6ppc, N133 Panda Sporter, good barrel and good bullets seated just off the lands.( all BR rifles in use today behave the same way.) Go either way and it will tell you what you want to know. If you go UP .3 and the group opens up to two bullet holes of vertical, you know you went the wrong way and the rifle is now completely out of tune. Go back where you were and then go DOWN .3 and the vertical should disappear. The rifle is now in tune under those specific atmospheric conditions with 26.7 grains. Most shooters don't like to shoot down in the first window so let's go up 1.2 grains to 27.9 and see what happens. Well I'll be darned. I guess we just jumped from the bottom stop to the wider, more forgiving top stop. Great! Go to the record! 
Now tell em' about tuners, Gene.When you have a barrel that is extremely sensitive to tune, you are very likely tuned to the 'bottom stop' of the barrel's vibration cycle.
It is now widely understood that bullet exit timing relative to where the muzzle is pointing is critical for best accuracy and widest tune window. As the barrel vibrates and the muzzle goes through its 'whip cycle' it comes to a complete stop at the top and bottom. There are two in-tune sweet spots; one just before the top stop and another just after the bottom stop. Both sweet spots occur as the muzzle is on the way up, providing what is known as 'positive compensation' for variations in muzzle velocity; slow shots exit when the muzzle is pointed higher, faster shots exit when the muzzle is pointed lower. The rifle will shoot well at either spot but the upper sweet spot, just before the barrel reaches the apex of its swing is much more forgiving and the rifle stays in tune through greater changes in atmospheric conditions. "So how in 'ell do you tell which is which?"
In his book, "Extreme Rifle Accuracy" Mike Ratigan describes a very critical, sensitive tune as being like trying to 'balance razor blades." Now you know what he meant.
Understand that if we were to start tuning at the lowest practical load of let's say 27 grains N133 for the 6ppc, we would encounter an 'in-tune' condition every 120 fps as we gradually increase the charge by .3 grain increments up to a maximum of around 30.2 grains. Expressed in grains of powder the sweet spots occur every 1.2 grains. Some rifles shoot terrific at 27 grains but rarely are we so lucky to be right in tune starting out, but even if we start out completely out of tune which is indicated by two bullet holes of vertical at 100 yards, we can't be more than .6 grains in either direction out of tune!
No matter where you are between 27 grains and 30.2, you can't be more than .6 grains from either the top stop or bottom stop. If the rifle shows in tune at the particular time, (no vertical) go to the record!
Start at 27 grains. 3 shot test groups show one bullet hole of vertical indicating the rifle is only .3 grains from one or the other sweet spots. But should we go UP .3 grains or DOWN .3 ? Simple.
Okay, second match of the day. We notice temp has increased about ten degrees from the early morning low of 60 so we know the rifle is not likely to be in tune, but who cares; we're going to re-tune anyway. We want to shoot up in the 27.9 to 28.0 grain range so lets start out with 28 grains. A three shot test group shows no vertical!
Now, for match three, temp has increased to 75 degrees but we don't change the load hoping that positive compensation will take care of us. The record group was good with only one bullet hole of vertical so we know the 15 degree increase in temp is beginning to show so we lower the charge from 28 grains to 27.7 for match four.
Match four. Temp is now 80 degrees so we reduce the charge to 27.4 just to be safe. Sure enough, the three shot test group shows no vertical so our calculations were correct. If temp remains the same or doesn't increase by more than five degrees we know we are safe to go to the line for match five with the same load.
Make sense? Questions?
Hope Keith Sharp (MKS) will join in. He explains things so much better than I do.
Later,
Gene Beggs
Now tell em' about tuners, Gene.
Yep, I was saving that for last, Mike. After comparing how complicated, time consuming and frustrating tuning with the powder charge is, I hope to convince the skeptics how easy it is to tune with the tuner.
You know it, I know it and many others know it but might be keeping it to themselves.
Later,
Gene Beggs
The rifle is now in tune under those specific atmospheric conditions with 26.7 grains. Most shooters don't like to shoot down in the first window so let's go up 1.2 grains to 27.9 and see what happens.
Okay, second match of the day. We notice temp has increased about ten degrees from the early morning low of 60 so we know the rifle is not likely to be in tune, but who cares; we're going to re-tune anyway. We want to shoot up in the 27.9 to 28.0 grain range so lets start out with 28 grains. A three shot test group shows no vertical!
...
Make sense? Questions?
I could simply make an adjustment to the tuner at the line and never have to change the load, EVER. ""But what if you go the wrong way?? Simple, if the image get worse, you went the wrong way; go back the other way till it gets clear.
I'm listening and I agree, Gene. Tuners are so easy to use it's crazy, and they work as you've described, IME. The only thing I'll add is that the needed adjustment is nominal in that different tuners, threads, weight, position relative to muzzle, barrel STIFFNESS, etc., all come into play in determining just how far the tuner needs to be moved for a given effect.Hunter
You are a man who pays very close attention to everything said and you are absolutely correct.
What are you missing? Nothing!
I used a poor choice of numbers in the example above probably because I've been working with a shooter in the tunnel that prefers to shoot at the extreme lower window of the 6ppc. We were using XBR powder at 26.8 grains to start with. The numbers got mixed up in my feeble mind.
In 100-200 yard group shooting with the 6ppc, there are many powders in use but the standard by which others are measured is Vit., N-133. Some are faster burning and this will affect how much change it takes to compensate for changes in atmospheric conditions; mainly temp increases. The recommended adjustment of .3 grains per five degrees temp change was worked out over several years of simply observing what it took to keep the rifle in tune as the day warmed up. Nothing in benchrest is absolute and the numbers we use to tune are only close approximations to get us in the ball park. Scales and powder measures vary by around plus or minus .2 grains and some powders burn a little faster than others so trying to predetermine exactly what the load should be is futile. The only sure way of knowing what the load should be is to listen to what the rifle is telling you with the test groups it prints on the sighter;
* Little or no vertical? 'I'm in tune, go to the record.'
* One bullet hole of vertical? 'I'm about .3 grains out of tune, one way or the other. Which way? Go either up or down and I'll tell you by showing either no vertical or two bullet holes in which case you went the wrong way.
* Two bullet holes of vertical? 'I'm completely out of tune. Go up or down around .6 grains or so and I should be reasonably in tune at either the top or bottom stop of the muzzle swing. But which one? Beats the 'ell outta' me!
"Damn, I knew I shouda' bought one of those Beggs tuners years ago, then I wouldn't have to be carrying all these different loads to the line.
Yep, it's true, believe it or not. Getting the rifle in tune by adjusting the tuner is just like adjusting the focus on an old Leupold 36 target scope. How do you get one of those beautiful old 36's in focus? Why, you loosen the lock ring and rotate the focus ring in one direction or the other till the target image is clear.
Now,,, what about focusing a tuner/barrel??? Same way as focusing the scope. With a Beggs tuner which is 28 tpi thread, you cannot possibly be more than a half turn out of tune. Shoot a 3 shot test group on the sighter. The rifle will tell you one of three things;
1. Little or no vertical; I'm in tune. Go to the record.
2. About one bullet hole of vertical; I'm only about a quarter turn out of tune. But which way? Reach up there and give the tuner a quarter turn in either direction. If the next test group increases to two bullet holes of vertical, you went the wrong way. (That's usually what happens to me.) Go back where you were and make a quarter turn in the other direction and you'll be in tune. Go to the record.
3. Two bullet holes of vertical; fully out of tune. A half turn in either direction will put the rifle in tune. But will I be tuned to the top or bottom stop? Who cares? In tune is in tune.
Hope this helps. For a while, I was beginning to think no one was even listening and didn't care to discuss this further.
Later
Gene Beggs
You do not...at least not with any tuner and barrel that I've ever seen.I'm listening and I agree, Gene. Tuners are so easy to use it's crazy, and they work as you've described, IME. The only thing I'll add is that the needed adjustment is nominal in that different tuners, threads, weight, position relative to muzzle, barrel STIFFNESS, etc., all come into play in determining just how far the tuner needs to be moved for a given effect.
Therefore, rather than matter of factly stating that every gun and tuner will be completely in or out of tune with a 1/2 turn...I simply state that small adjustments matter, to be very much methodical when testing, that big swings are likely to make you miss a tuning node and that once you establish what in and completely out of tune are relative to tuner movement, I've never seen the need to adjust beyond that small window of movement. IOW, If you're gun is completely in tune at the zero mark on the tuner, and completely out at the 4 mark..there is no reason to adjust anywhere beyond that zero to 4 range. I will add to that, that because as you pointed out, the tune will repeat itself. So, if you're completely out of tune it doesn't matter which way you go. you could go back to zero...or you can go to 8, and be back or very near in tune. IME, a tuner will be just as effective if it only had a single revolution(or less) of total range of motion, as with inches of threads on the barrel.
I suppose it's human nature to see all those threads and assume you need to use them.
There are seemingly endless conversations..or debates about HOW tuners do what they do and they all get confusing. But the important thing is that while they are hard to understand how they do what they do, it couldn't be simpler to use one. Just get your information from the person that made your tuner and forget about how far anyone else says to move your tuner. It's apples and oranges. They all work on the same principle, but that's where it ends.
