Harmonic Barrel tuner

It is not going to magically fix a poorly tuned gun. How is your accuracy now??

A harmonic barrel tuner is nearly the last step in fine tuning, Imho. I have the FX brand add on tuner for my Kral .25. that gun already shoots dang well, and the changes are subtle but definite. At one point in the range, I get two distinct one hole groups...one low left and one high right. Further along the adjustment range, the groups merge into one single area. This gun has a sweet spot of 60 shots...SD of 1 and an extreme spread of 8. If the gun was erratic, the fine changes would be lost in the data noise.

My suggestion is to tune as tightly as you can first, then worry about the dynamic tuner gadget.
 
I have been playing with them on three different guns, they can change things! A good shooting pellet is hard to tell? But I have made them shoot worse, so my thoughts are at some point I can make them shoot better? I’m along way out and several tins in! So ??
With slugs, a little further along, I don’t want to mislead, but they do change your groups, or should I say, you can change your groups? will they be consistent? Will they require constant adjustment? Will every elevation and temp change require starting over? I can’t say yet? I will say to do it right, ya better have a lot of time and know the full potential of your gun first! As stated very well above.

Also, you will need a good indoor range with zero or very little weather, the changes are pretty small. I will say, you might make a bad harmonic tune, shoot much better? They might just be the deepest rabbit hole of all? More to come in a month or 2! 


 
I had one--does it change your groupings? Yes. I live in MN though and got it as late summer was turning into fall/winter. Due to the wild weather swings, I did find it inconsistent from day to day. I found I didn't have the patience to retune the whole thing to go shoot for the day or afternoon. I also found the weather change had more of an effect with the tuner vs without.

It won't magically make a 2" group shrink down to .5", that's the tune. Can it help shrink down from 1/2" to 3/8"? Yes. Other issue, I tend to change calibers and slugs every now and then. Was it worth all the fiddling with the damn thing? Nope! 

I would like just a cf shroud though...one more thing, it does make your gun a bit louder.

Just my 2 cents. 
 
I have yet to see any significant harmonic effects on my .30 M3 (no tuner). Ronin vs Sumo, 50fps sweeps 1 or 2 clicks at the time on the micro adjuster, +-10bar reg pressure. It is really hard to see any changes at 100 yards. I'm talking maybe 1/4-1/2MOA at most. Ronin vs Sumo specifically I couldn't see any difference, and those two have significant weight differences. This suggests to me that I probably wouldn't benefit much from a harmonic tuner. 

One thing, though, is none of my tunes are pushing the gun that hard and I don't have the slug power kit installed. I suspect that maybe if you were shooting at the top of the guns power range, that you might see more harmonic effects and benefit from the tuner. I also wonder, at least with regard to the FX liner system, if there isn't some difference in severity of harmonics between the calibers. A .22 liner is a lot smaller in diameter than a .30.

I'm in the camp that's not convinced and watching for more feedback.
 
Last year I was retuning like the entire year, this year no, one gun stay one calibre, one projectile weight and one speed. Index the barrel to that projectile, make it all right no shortcuts, no attachments to barrel. I believe you make it right 98% and the barrel tuner can give you that remaining 2%. And then the winter hits and all gone. Orings get harder, any contact in between metal parts is moving harder, the air pressure is not cooperating...Now waiting for April.