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Barrel harmonics can and generally do, affect precision with regards to group size and point of impact.
Barrel harmonics are affected by weights on the end of barrels, and their position on the end of the barrel. Many weights are somewhat adjustable as to position - e.g., the Browning BOSS system and similar devices.
Harmonics are also affected by barrel stiffness. Diameter, length and material are all factors in barrel stiffness. Generally, all other variables being the same, a shorter barrel is stiffer.
There are also tensioned barrels. Some barrels have, in effect, a shroud, where the muzzle and chamber ends of the barrel act to tension the barrel, to make it straighter and less affected by barrel harmonics. Some carbon fiber barrels offered for rimfire rifles have this feature.
I owned a M1A2 bullpup that had a "bridge" to tension a stiff 1" diameter Krieger barrel. It was tuned by adjusting the torque of the "nut" towards the muzzle end of the barrel. The tuning from the customizer/seller (AWC) was for Federal 168 gr HPBT Gold Medal match ammo, which shot sub 0.5 MOA groups in my hands, and I am not that good of a shot.
I also owned a Dan Wesson .44 mag revolver with a tensioned barrel - it was the most accurate revolver I have ever shot - again, I am not that good of a shot.
So I am partial to tensioned barrels from people who know what they are doing.
Barrel harmonics are affected by weights on the end of barrels, and their position on the end of the barrel. Many weights are somewhat adjustable as to position - e.g., the Browning BOSS system and similar devices.
Harmonics are also affected by barrel stiffness. Diameter, length and material are all factors in barrel stiffness. Generally, all other variables being the same, a shorter barrel is stiffer.
There are also tensioned barrels. Some barrels have, in effect, a shroud, where the muzzle and chamber ends of the barrel act to tension the barrel, to make it straighter and less affected by barrel harmonics. Some carbon fiber barrels offered for rimfire rifles have this feature.
I owned a M1A2 bullpup that had a "bridge" to tension a stiff 1" diameter Krieger barrel. It was tuned by adjusting the torque of the "nut" towards the muzzle end of the barrel. The tuning from the customizer/seller (AWC) was for Federal 168 gr HPBT Gold Medal match ammo, which shot sub 0.5 MOA groups in my hands, and I am not that good of a shot.
I also owned a Dan Wesson .44 mag revolver with a tensioned barrel - it was the most accurate revolver I have ever shot - again, I am not that good of a shot.
So I am partial to tensioned barrels from people who know what they are doing.
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The barrel weight attenuates the harmonics of the barrel and dampens the barrel whip amplitude.
Edit to add:
adjustment of the weight or position of weight is ideal to avoid having a dampener that operates at the same natural frequency as the barrel harmonics. To give an example of this:
If the upward whip force of the barrel moves the weight enough that its natural rise apex is synchronized with the max force wave of the barrel whip, and then begins to fall, it can significantly worsen the harmonics by increasing the downward force on the barrel.
Edit to add:
adjustment of the weight or position of weight is ideal to avoid having a dampener that operates at the same natural frequency as the barrel harmonics. To give an example of this:
If the upward whip force of the barrel moves the weight enough that its natural rise apex is synchronized with the max force wave of the barrel whip, and then begins to fall, it can significantly worsen the harmonics by increasing the downward force on the barrel.
Last Edited:
I looked into it and decided it wouldn't be worth it for NRL but could be for bench rest at a single distance...this type of shooting doesn't really interest me, so I gave up the research.
The idea with rimfire tuning is to adjust the whip to compensate for changes in velocity. Ideally, the slower rounds in a group get lobbed at the right angle for them while the faster rounds exit at a slightly different angle...the whole thing culminating in rounds that hit paper in the same spot at some known distance regardless of the velocity spread of the rounds.
How well will the barrel take to tuning? Seems dependent on the length and profile, with longer thinner barrels (26" and < .920") reacting more to the tuner.
What should be noted is that you are correcting only for vertical spread. If the rifle already shoots well or has issues in horizontal spread, then a tuner may not be of benefit.
Additionally, if the velocity spread changes (like changing ammo or lots), then re-tuning will likely be necessary.
Since velocity, distance, and drop are all linked - changing target distance may also require re-tuning. A tuned 50yd set up may not be the best for 100yd which again may not be the best for 200yds. There are a lot of forum posts about tuners who just took the rig off because it would work at some range but then be worse than before at another range.
If you get into it, I'd love to see the test results. After learning that it is distance dependent, I abandoned the idea in favor of just shooting lots of different ammo and seeing which one works best with the stock barrel.
The idea with rimfire tuning is to adjust the whip to compensate for changes in velocity. Ideally, the slower rounds in a group get lobbed at the right angle for them while the faster rounds exit at a slightly different angle...the whole thing culminating in rounds that hit paper in the same spot at some known distance regardless of the velocity spread of the rounds.
How well will the barrel take to tuning? Seems dependent on the length and profile, with longer thinner barrels (26" and < .920") reacting more to the tuner.
What should be noted is that you are correcting only for vertical spread. If the rifle already shoots well or has issues in horizontal spread, then a tuner may not be of benefit.
Additionally, if the velocity spread changes (like changing ammo or lots), then re-tuning will likely be necessary.
Since velocity, distance, and drop are all linked - changing target distance may also require re-tuning. A tuned 50yd set up may not be the best for 100yd which again may not be the best for 200yds. There are a lot of forum posts about tuners who just took the rig off because it would work at some range but then be worse than before at another range.
If you get into it, I'd love to see the test results. After learning that it is distance dependent, I abandoned the idea in favor of just shooting lots of different ammo and seeing which one works best with the stock barrel.
The adjustable muzzle weight tuners clearly worked in RF benchrest. Everyone serious in the game had one, and my testing showed a significant improvement once you found the right setting. This is on big, awkward, BR purpose-built game guns. They are pointlessly stupid in any kind of practical rifle. The one exception might be that rubber sex-toy-looking
I don't recall hearing that tuners varied by range. The idea at the time I was in the game was that the muzzle whipped/vibrated from the shot, and the tuner moved the muzzle end to either an apex or vertex of that wave, where it was moving the least. And that reduced the variability in muzzle position at bullet's exit. But we shot at 50 yds, and sometimes also at 50 yds, and occasionally even at 50 yds. So there is that….
LimbSaver Sharpshooter X-Ring Barrel Dampener
that you slide up and down the barrel, if you could find a spot that made a difference.I don't recall hearing that tuners varied by range. The idea at the time I was in the game was that the muzzle whipped/vibrated from the shot, and the tuner moved the muzzle end to either an apex or vertex of that wave, where it was moving the least. And that reduced the variability in muzzle position at bullet's exit. But we shot at 50 yds, and sometimes also at 50 yds, and occasionally even at 50 yds. So there is that….
The theory of attempting to modify the barrel's natural whip such that you move the apex or vertex of the wave to just on/after the crown so that bullets exit at the literal same spot every single shot...I think this has merit...but don't see how it would help you (specifically with rimfire, where velocity is not as controlled).
Assume that you could get a perfect trajectory coming from the same spot for every shot. Perfectly tuned whip to the degree that there is no whip - the barrel is perfectly at that apex/vertex mark. Your first round fires and is heading at 1040fps. You fire again, this time the round travels at 1060fps.
The bullets exited the barrel at the exact same spot...but what would be expected downrange? I'd expect the faster bullet to impact slightly higher than the slower bullet.
Tune the whip is what I mention above...you want the whip - specifically so you can lob the slower rounds further and let the faster ones take on a straighter trajectory...thus they all end up around the same POI. The harmonics/whip is going to be relative to the round; the first pew moving 1040fps will not induce the exact same whip as the one moving 1060fps because they have different forces that they're applying on the barrel.
That's the theory anyway.
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A stiffer barrel has less harmonics, and therefore less variation in harmonics. At least in my experience.
In rimfire BR, the ammo is expensive, well made/quality controlled Eley & Lapua. The SDs are small, tho I agree a range of 20 fps is pretty likely. The purported reason to be at peak or trough of sine wave is because there is the least movement per time unit at the top or bottom, because the movement is slowing down, then still, then starting up again. The most movement per time unit is in between.
I don't know how small velocity differences play into location of the muzzle, or if the tuner transforms that function so that it is somehow the same proportion for each velocity, or if the sine wave theory espoused when I played that game is correct at all. I would GUESS that the powder charge burn accounts for the vibrations, and that MV is dependent on powder burn plus bullet & bore factors. I also don't know how much difference in POI there is between a 1040 fps shot and a 1060 fps shot at 50 yds from a perfectly still muzzle. I do recall that MV SD had no apparent relationship to group size in 50 yd RF BR. I do know that the best tuner setting didn't seem to change for different lots of ammo, and that some lots shot great and others stunk and a great lot was VERY apparent in a few shots, even tho you tested more to make sure.
I don't know how small velocity differences play into location of the muzzle, or if the tuner transforms that function so that it is somehow the same proportion for each velocity, or if the sine wave theory espoused when I played that game is correct at all. I would GUESS that the powder charge burn accounts for the vibrations, and that MV is dependent on powder burn plus bullet & bore factors. I also don't know how much difference in POI there is between a 1040 fps shot and a 1060 fps shot at 50 yds from a perfectly still muzzle. I do recall that MV SD had no apparent relationship to group size in 50 yd RF BR. I do know that the best tuner setting didn't seem to change for different lots of ammo, and that some lots shot great and others stunk and a great lot was VERY apparent in a few shots, even tho you tested more to make sure.
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