ladder test with a tuner
- Thread starter RJM
- Start date
I don't do ladder tests, so I can't answer that part of the question. I mainly shoot score matches as there is no group competition in my area.
I go to all matches preloaded for both yardages (100/200). I use the initial 3 minute sight in (100 yards) to set the tuner. I shoot two shots and if there is more than 1/2 bullet vertical I stop adjust the tuner about 1/8". The direction depends on the temp as compared to the last time I adjusted. If the two shot group had no discernible vertical I take a third shot to confirm. I do this again when we move to 200 yards. When I have neglected to do this, it's usually been a mistake. Most of the time the temp changes from 9:00 -12:00 and requires another slight adjustment. I never change the powder charge, only the tuner setting. Depending on the barrel contour and load, one might find a setting that rarely needs changing. I just retired a 1.25" straight barrel chambered in 220 Beggs that I almost never changed and even then, only slightly. My LV barrels seem to need more frequent adjustments, but I don't believe I've adjusted at all during a yardage. However, there have been times that maybe I should have.
Rick
jackie schmidt
New member
Truth is, I have a load with N133 in a .237 4 groove 13.5 twist Krieger that is always pretty close. I stick that load in it, and then tune with the tuner. It is in what many of us call "the upper load window".
The only time I won't do this is if the humidity drops way down in the 20 percent or lower range. I know then to put about as much powder in the case as a 12 in small hole drop tube will allow. Or settle for middle of the pack.
If the barrel won't shoot that load reasonably well with minor tweaks of the tuner, it's getting discarded.
The only time I won't do this is if the humidity drops way down in the 20 percent or lower range. I know then to put about as much powder in the case as a 12 in small hole drop tube will allow. Or settle for middle of the pack.
If the barrel won't shoot that load reasonably well with minor tweaks of the tuner, it's getting discarded.
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M
mks
Guest
Below are the results of a tuner test. I wouldn't call it a ladder test, more of a "cross test," because what you get as you move the tuner is a vertical group that changes to round, then to horizontal then to round, then to vertical, etc., in a repeating pattern. The results below are a coarse test moving the tuner two marks at a time and the round groups don't show up. (Sorry, I couldn't find exactly the right set of results to show this, but it is what I have found to happen.) The round groups would be in between these tests at tuner settings of 11, 9 and 7. Also, the group at tuner setting of 12 doesn't quite fit the pattern. It does have more vertical like tuner 8, but there is also some horizontal that may have crept in from a little wind. Or the patterns may just be inconsistent at this point. Note that the tuner goes through its whole cycle of group shapes in 4 marks, which is an eighth of a turn of the rings.
Keith,
I just have a couple of comments on your post. I'm guessing that these groups were shot at 200 yards as most ladder tests are done at that distance. Also, since I wasn't there I can only guess at the wind conditions.
IME- you have gone from in tune to out of tune with a fairly large movement of the tuner. 1/8 of a turn (again IME) is a very large adjustment. Most of my tuning involves 1/8" of movement of the tuner. The groups you posted indicate to me that #2 & #4 were pretty much in tune, but the seating depth needs to be changed slightly. Of course, that could also be the wind you mentioned. IME, with every type of tuner I own, on a LV barrel 1/8 of a turn would take me in and out of a node a couple of times.
Rick
M
mks
Guest
Rick,
The round groups that I unfortunately couldn't find graphs of are the smallest, so these represent the best tune. These occur every two marks (one mark = 1/32 of a turn = 0.001" axial movement) and are in between the tuner settings of the graphs shown. So I think this part of our experience is similar.
We seem to do different things about a horizontal group, though. I hadn't thought of changing seating depth to reduce horizontal, so thanks for the idea. I just turn the tuner one mark and the horizontal goes away. It still seems incredible that it works this way, that this rifle is only ever one mark away from tune. It may not always be consistent, as the first graph shows, but it is remarkably so. For seating depth and powder charge, I find the smallest groups with each of these at one setting of the tuner, then don't change them afterward. The only tuning is with the tuner. I don't bring a press to the range, and I would have to start doing that to change seating depth. So long as it is doing the job, I like the convenience of using only the tuner. But I'll keep seating depth in mind if I ever have problems.
Thanks,
Keith
Keith,
Your additional comments do seem to show similar results to mine. It only take very small adjustments to have an effect on the tune. I wish I could claim discovery of the seating depth and horizontal, but I'll have to give credit for that to Gene Beggs. A couple of years ago I exchanged several emails with him and learned that he adjusts the vertical with the tuner and the horizontal with seating depth. (If I misunderstood him or if he has found other data, I hope he'll see this and add to it).
When I get a new barrel (which I did last week) I begin with a known good load. If it responds well to the tuner, I begin adjusting the seating depth. I have found that after finding a good seating depth I can tune the vertical with the tuner and it has no ill effect on the horizontal. However, if the vertical tune is bad, the horizontal will also be bad. Hope that makes sense.
YMMV,
Rick
M
mks
Guest
Rick,
Thanks, makes perfect sense. But with the difference we see (your tuner doesn't affect horizontal, but mine does), it makes me wonder what causes it. I have only tested two rifles with tuners. They have essentially the same action, barrel and tuner, but very different stocks. Yet they respond pretty much the same to tuner setting. Is your tuner a Shade Tree? I'll bet our barrels are about the same (HV contour). Is your action single or dual port?
Thanks,
Keith
Thanks, makes perfect sense. But with the difference we see (your tuner doesn't affect horizontal, but mine does), it makes me wonder what causes it. I have only tested two rifles with tuners. They have essentially the same action, barrel and tuner, but very different stocks. Yet they respond pretty much the same to tuner setting. Is your tuner a Shade Tree? I'll bet our barrels are about the same (HV contour). Is your action single or dual port?
Thanks,
Keith
Keith,
It may well be that I just haven't noticed about the tuner affecting horizontal. There is a long range shooter in Florida that insists in a thread on accurateshooter.com that he gets the same results that you report. Maybe I will need to watch closer, but for now as long as I can get consistent horizontal with seating and good vertical with the tuner, I'll probably stick with that process. When I can get the time to spend at the range for something other than a match, I'll see what I can find out. As far as tuners, I have at least seven different types. Currently, I'm using a Borden on two and an Ezell on the other, the fourth is a Factory Class so I can't use one on it. I think I still have a Shadetree somewhere.
Rick
M
mks
Guest
Rick,
The reason I ask about the actions is that most don't have the same stiffness on the left as the right, especially single port. Even dual port actions usually have different size ports, so the stiffness in not perfectly symmetrical. Asymmetrical stiffness would tend to cause more horizontal, which the tuner alone might not be able to eliminate. There could be other reasons, too, why a tuner doesn't take out horizontal on a particular rifle.
Keith
OK, I guess I didn't completely understand you question. Since you don't shoot UBR with us, you wouldn't know that I am one of the very few idiots that shoots all four classes and a completely different rifle in every class.
Factory Class -Remington 40x 6x47 (222 RM), no tuner
Modied Class - Remington 40X 6PPC HV barrel Borden Tuner
Custom Class - Bat "S" RB, Dual port, 6PPC LV barrel Ezell tuner
Unlimited Class - Remington XP (Sleeved) 220 Beggs Straight 1.25" - Borden Tuner
So each rifle/class is different and I typically shoot two rifles at every match. They all shoot a little different, so it's not unusual that I would miss some subtle differences in the tuner effect.
Rick
mwezell
Mike Ezell
If you're referring to the change in poi, yes, I count on it. I just don't adjust in the middle of a string.
Is there something else I should be looking for, Gene?
I think that's close to what I was referring to as a ladder test with the tuner. Can you provide some additional explanation of the picture?
My naive thought is that if you can find a range of settings where the shots go to the same POI, set the tuner in the middle of the range, & call it tuned.
Regards,
Ron
Maybe Gene can provide that info. It's my understanding that he uses the tuner a bit differently than I do. I think he gets he best tuner setting, locks it down and then adjusts the load as conditions change. maybe he will clarify that.
IME, any change of the tuner setting will change the POI. As I mentioned in an earlier post, my changes are all very small, but all have an effect.
Last Saturday, when I began shooting, I had a little more than a bullet overlap of vertical. I moved the tuner to the left about 1/8" and removed the vertical. I don't think picking a "range" of settings would work as each adjustment, no matter how small will have an effect. It seems that what you are looking for is a way to shoot without changing the tuner settings. You could do this, but IMO it would defeat the purpose. I go to every match preloaded. The tuner gives me the ability to change the tune as the day warms up or as is frequently the case, change the tune when the day begins much colder than when I previously tuned it.
I look forward to Gene's input on this.
Rick
M
mks
Guest
Gene,
That is an enlightening test. I just want to point out a difference between your test and what "tuner twisters" hope to accomplish when they adjust the tuner throughout the day. Your shots I assume were all made under the same conditions (the same temperature, particularly). Whereas what a tuner adjustment after a temperature change is supposed to do is to bring the response of the rifle back to the same as it was at some previous temperature. That is, we want the angular position and angular velocity of the muzzle when the bullet exits to be the same as before, which gives us the same POI and the same compensation for variation in barrel exit time.
What happens when temperature increases is that the bullet exits earlier and MV increases. Then we try to compensate by changing the dynamic response of the barrel to make it move quicker. Change B to bring us back to level, even though it was A changed, so to speak. Because the response of the barrel after the muzzle mass is shifted can be different in a number of ways, the adjustment may be imperfect, and not restore the POI and/or compensation exactly.
I am probably telling you something you already know. This may be your reasoning behind leaving the tuner alone, and bringing bullet exit time and MV back to the same by using less powder. It make sense. By doing so, there is a greater likelihood that all the conditions will be the same. All I can say is that adjusting the tuner sometimes does pretty well, and is more convenient. I have not seen large shifts in POI when I adjust the tuner along with a temperature change, but I do when I adjust it at constant temperature.
Cheers,
Keith
M
mks
Guest
I think the range of tuner settings we want to use would be one over which POI decreases smoothly as the tuner is moved in (toward the receiver). Stay away from any range where jumps occur. You could leave it in the middle of the range and tune with powder charge, or you could leave powder charge constant and move the tuner as temperature changes. You have to change something to keep it tuned.
Gene, I wonder if the tuner settings at which the peaks and valleys in your POI occur depend on temperature. I would think so, but have never tested that way.
Thanks,
Keith