Anxious for clear weather to try Beggs Tuner
- Thread starter Jim Borden
- Start date
J
J. Pendergraft
Guest
Tuning for Various Distances
I think most of us believe that one tuner (muzzle device) setting is not going to deliver the best accuracy at all distances. At present I shoot competitively 1000 yards so my interest is how to find the best tune for that distance without having to test at that distance.
Using my Pejsa ballistics program I input the data for 2 typical 30 cal loads with a 50 fps difference in muzzle velocity. The program indicates the slower bullet must track .85" higher at 100 yards to impact the same point at 1000 yards. This may sound extreme but I have found this program to be quite accurate.
I am thinking that I could load 2 sets of ammo that vary in velocity on average 50 fps. I would then shoot at 100 yards and adjust my tuner where the average impact of the slower bullets is about .85" higher than the faster bullets. Does this sound like a sound approach?
Jackie, I would be interested to know if the best tuner setting for your 6PPC at 100 yards works for 200 yards as well. My guess is it will not.
I think most of us believe that one tuner (muzzle device) setting is not going to deliver the best accuracy at all distances. At present I shoot competitively 1000 yards so my interest is how to find the best tune for that distance without having to test at that distance.
Using my Pejsa ballistics program I input the data for 2 typical 30 cal loads with a 50 fps difference in muzzle velocity. The program indicates the slower bullet must track .85" higher at 100 yards to impact the same point at 1000 yards. This may sound extreme but I have found this program to be quite accurate.
I am thinking that I could load 2 sets of ammo that vary in velocity on average 50 fps. I would then shoot at 100 yards and adjust my tuner where the average impact of the slower bullets is about .85" higher than the faster bullets. Does this sound like a sound approach?
Jackie, I would be interested to know if the best tuner setting for your 6PPC at 100 yards works for 200 yards as well. My guess is it will not.
I think it will. Drop is drop, gravity being 32ft/sec^2
As I see it, we get vertical (1) because the slower rounds "take longer" to get to the target, (2) because drag is not constant across all bullets, and (3) the barrel moves, so the position & angular velocity of the muzzle changes.
We have to accept (2) -- or trim meplats, point bullets, whatever. The good news is we can use (3) to compensate for (1). We can do this either by tuning the load, or a muzzle devise. The hope of the Calfee muzzle devise (tuner) is that we can get compensation over a rather wider range of velocities than a conventional "tuner," because the bad part of (3), i.e., when it is working against you, can be eliminated or at least, minimized. If the muzzle absolutely didn't (a) move or (b) ever take an angle, there would be no "tuning," (where "tuning" means compensation for velocity differences). But as Varmint Al's model showed, that's not the case.
What am I missing?
J
J. Pendergraft
Guest
Same tuner setting for 100 and 200 Yards ??
Back to my trusted ballistics program. Shooting a 68 gr bullet (BC .276) at3400 fps and shooting the same bullet at 3425 fps. I understand some easily have this much velocity deviation in their 6 ppc rounds.
You tune your rifle such that bullets of both these velocities go in the same hole at 100 yards. These same 2 bullets if they traveled undisturbed on to 200 yards would show a dispersion of .060".
This is why I think you need a different tuner setting at 100 yards vs. 200 yards for optimum accuracy.
Back to my trusted ballistics program. Shooting a 68 gr bullet (BC .276) at3400 fps and shooting the same bullet at 3425 fps. I understand some easily have this much velocity deviation in their 6 ppc rounds.
You tune your rifle such that bullets of both these velocities go in the same hole at 100 yards. These same 2 bullets if they traveled undisturbed on to 200 yards would show a dispersion of .060".
This is why I think you need a different tuner setting at 100 yards vs. 200 yards for optimum accuracy.
I don’t think its just a velocity thing, its been forever since I’ve done a ladder test @200 but from memory the bullets tended to climb dramatically between the in-tune clumps, they also had some side to side movement depending on the velocity node. So if your tune is on the upper or lower edge of an accuracy window you end up with more vertical than velocity alone would ever account for.
I have no idea how this is going to play out in the end and that’s why its so interesting. Will a ladder test give a linier velocity climb without side-to-side shifting and clumps, or wider tuning nodes (clumps) with the same amount or less vertical between them, or one ragged bug-hole @ 200 that’s impossible to tune at 100.
Interesting stuff!
B
BJS6
Guest
I have been doing a lot of reading of old posts and of Bill's article and of Varmint Al's analysis.
Seems to me nobody can actually say with 100% scientifically proved certainty just how a barrel actually vibrates under the forces imposed by firing the rifle.
Bill says it flops about the same as a natural vibration with a nice dead area back from the muzzle and a little area near the muzzle that moves up and down. It is this last area that is said to be able to be controlled with a tuner.
Varmint Al analysed the recoil effects etc on the barrel vibration and has presented 5 different vibrations patterns that are all happening at once. One has the entire barrel wobbling up an down such that even if you controlled that little end piece of the barrel with a tuner the whole barrel is still going up and down as well as in the mode that Bill talks about as well as even higher frequency vibrations as well as length increase.
Several posters are also saying that the natural frequency has nothing to do with what happens when the rifle is fired.
How can we be sure of what tuner design will work, how to determine the weight needed and how to adjust it correctly if nobody knows for certain how the barrel is even vibrating !! ??
Several people are talking like they have it totally figured out and why the tuners work. Funny thing is the best scientific analysis that I have seen (Varmint Al's) contradicts this, that is the whole "stopped muzzle" thing. In fact Varmint Al uses al lot of if's, but's and maybe's in his text because it seems he isn't convinced of how a barrel vibrates and how a tuner works even after all his computer modelling and analysis.
I am coming around to thinking that all any tuner does is slow the frequency of the barrel movement and allow some degree of control of the muzzle movement. The muzzle my be stopped in one vibration mode but not in the others ???
Unless ........... perhaps the first mode of vibration is slow enough that any decent load will exit the barrel consistently enough to shoot well, the second can be controlled like Bill says and the 3rd modes of vibration and higher are so fast and small that they make no practical difference anyway. Perhaps there is only one mode of vibration that needs to be controlled even though there are several happening all at once ??????
My head hurts !!!
Bryce
Seems to me nobody can actually say with 100% scientifically proved certainty just how a barrel actually vibrates under the forces imposed by firing the rifle.
Bill says it flops about the same as a natural vibration with a nice dead area back from the muzzle and a little area near the muzzle that moves up and down. It is this last area that is said to be able to be controlled with a tuner.
Varmint Al analysed the recoil effects etc on the barrel vibration and has presented 5 different vibrations patterns that are all happening at once. One has the entire barrel wobbling up an down such that even if you controlled that little end piece of the barrel with a tuner the whole barrel is still going up and down as well as in the mode that Bill talks about as well as even higher frequency vibrations as well as length increase.
Several posters are also saying that the natural frequency has nothing to do with what happens when the rifle is fired.
How can we be sure of what tuner design will work, how to determine the weight needed and how to adjust it correctly if nobody knows for certain how the barrel is even vibrating !! ??
Several people are talking like they have it totally figured out and why the tuners work. Funny thing is the best scientific analysis that I have seen (Varmint Al's) contradicts this, that is the whole "stopped muzzle" thing. In fact Varmint Al uses al lot of if's, but's and maybe's in his text because it seems he isn't convinced of how a barrel vibrates and how a tuner works even after all his computer modelling and analysis.
I am coming around to thinking that all any tuner does is slow the frequency of the barrel movement and allow some degree of control of the muzzle movement. The muzzle my be stopped in one vibration mode but not in the others ???
Unless ........... perhaps the first mode of vibration is slow enough that any decent load will exit the barrel consistently enough to shoot well, the second can be controlled like Bill says and the 3rd modes of vibration and higher are so fast and small that they make no practical difference anyway. Perhaps there is only one mode of vibration that needs to be controlled even though there are several happening all at once ??????
My head hurts !!!
Bryce
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Butch Lambert
Active member
Go to this link and you will see Varmint Al's work on Esten Spear's rifle and tuner. http://www.varmintal.com/aeste.htm#Ladder
It is this work by these 2 talented guys that allowed us to offer this tuner for sale. This is Esten's design and Shelley built a few prototypes that are working very well.
We hope to have the Shadetree Engineering-Shelley tuners in no more than 3 weeks.
Butch
It is this work by these 2 talented guys that allowed us to offer this tuner for sale. This is Esten's design and Shelley built a few prototypes that are working very well.
We hope to have the Shadetree Engineering-Shelley tuners in no more than 3 weeks.
Butch