Barrel Tuners- Muzzle Breaks- Barrel Harmonics Management

[Veteran]

The directions on the rubber things say if barrel is free floating, place near end of barrel. If not, start about 1" from the chamber side.

Yes, seems like I have read that, that where you place at least the rubber rings is a function of free floating or not free floated barrel

 

[Veteran]

@Veteran Remember, changes in the axial direction of 0.001" make a significant difference on target. I have even moved tuners 1/2 an increment (0.0005") and watched my vertical dispersion cut nearly in half at 1000yds. Adjusting a moving mass requires a setup where you can accurately moves such small distances between groups...hence most are threaded in a very fine pitch.

Yes, I have no real experience with a real tuner so I have no idea of the sensitivity on the dispersion other than youtube videos I have watched. My rough cheapo shaft collar is only as sensitive as my eyeball and the micrometer I used to measure from the end of the barrel to the end of the shaft collar....... So, that makes me feel better about 10-12 oz. of weight being enough, if they are that sensitive to dispersion vs, axial adjustment, even on a big bull barrel.

 

[Veteran]

@Veteran Remember, changes in the axial direction of 0.001" make a significant difference on target. I have even moved tuners 1/2 an increment (0.0005") and watched my vertical dispersion cut nearly in half at 1000yds. Adjusting a moving mass requires a setup where you can accurately moves such small distances between groups...hence most are threaded in a very fine pitch.

Yes, I have no real experience with a real tuner so I have no idea of the sensitivity on the dispersion other than youtube videos I have watched. My rough cheapo shaft collar is only as sensitive as my eyeball and the micrometer I used to measure from the end of the barrel to the end of the shaft collar....... So, that makes me feel better about 10-12 oz. of weight being enough, if they are that sensitive to dispersion vs, axial adjustment, even on a big bull barrel.

 

[Radman]

First I watched every youtube video I could find on the subject, then I went out and bought some shaft collars, and couplers that would fit two of my rifles, and began experimenting a little. Lately, I read everything I could find on LRH from posts ranging from 2006 to present, then I searched for more details on the internet in general. I found Varmintal.com which is authored by a gentleman who retired from Lawrence Livermore labs, and spent his whole career running complex structural analysis on steel and other materials using models with time-steps and cells where the model calculates pressures, velocities, harmonics, and all the data 1 step and 1 cell at a time all the way from the ignition at firing down to the end of the barrel. This is called FEA analysis or Finite Element Analysis. He has a fascinating web site with a ton of science behind his conclusions. I understand harmonics because I had to have labs specializing in harmonic vibration on larger rotating compressors and machinery analyze harmonic vibrations which were tearing down multi-million dollar facilities.

Now, I know there are perhaps many on this site who will just say, you don't need a tuner, because if you reload, you can tune the harmonics out of your rifle with bullet seating, and powder selection and velocity/pressure optimization.

But, its clear to me from all the reading that I've done that there are just as many who will say, yes, you can get 70 or 80% there by bullet seating, and powder selection, and velocity/pressure measurement, and glass bedding, free floating, pillar bedding, and having a good stock. But there are just as many who will tell you they went from 0.5 MOA groups to 0.2 MOA groups or from 1 MOA plus groups to .75 MOA groups using a tuner after they did all of the above. It's maybe not critical for hunting in the 100-300 yard range. I usually shoot and tag 3-4 deer per year all from 30 yards to 150 yards max. But for long range hunting and ELR shooting, I would think any improvements in group size would be sort of important? Evidently, a lot more competitive benchrest shooters are using tuners than used to or were back in 2006? I have come to believe they can help improve groups even after good load development.

I'm looking for 1 ragged hole accuracy at 100 yards with all my rifles. So, I am considering buying and having a gun smith install tuners on several of my rifles.

Some of my questions were answered by my reading, and I had good results using my cheapo experiments especially on my .338 Lapua Magnum just using a $25 shaft collar that weighs about 1.8 lbs. It was hard for me to believe that part of my performance issues on MOA with this rifle were harmonics related, because it is a free floated barrel, and it's a big heavy barrel. I started to realize just how much pressure and velocity can affect even a big heavy barrel, and that all rifles have harmonics that have to be managed. My MOA went from around 1 down to 0.5 to .625 range when I installed the 1.8 shaft collar, using the same loads. That's when I knew that this rifle had a harmonics issue, even as big and heavy as it is.

My Lapua is the Savage BA 110 LE law enforcement model which weighs 17 lbs. with a 26 inch bbl. Plus Muzzle break, even with no scope etc. It's not a rifle I plan to carry further than from the car to the benchrest or to a portable benchrest looking out over a 500 or 700 yard long clear cut or wild flat canyon lands with a big view down on the Pecos in Texas. It's a firearm that is generally planned to be fired from a pre set or expedient station, not carried, certainly not in mountains.

Several things I have had on my mind. 1) How much weight is optimum for a barrel tuner, and does the length, and diameter and weight of the barrel have any correlation to that answer? I'm thinking that the 9 oz. to 12 oz. weights used in Harrell's and the EC Tuner may not be enough for a big heavy barrel? Nor may the muzzle brakes they build onto those tuners be sufficient or at least equal to what is already there. Its also clear to me that you can also overdo the weight of the tuner as Varmintal shows that in some of his experiments. How do you decide what is perfect for your rifle without running an FEA analysis? Someone must have some ideas or experience?

Since I have a standard factory Savage muzzle break on my .338 Lapua, what is the best tuner available commercially that incorporated an adequate or optimum break for a large caliber rifle if anyone makes one?

I know both Harrell's and Eric Cortina make tuners that incorporate muzzle breaks, but I need to make sure I get a good one for this rifle, and I don't care about weight vs. really good function.

Because the Savage factory muzzle break is designed with no ports on the bottom, it has more gas escaping straight up which forces the barrel downward too. Is this potentially one of my harmonics problems with the rifle? Is there a better muzzle break design for accuracy?

Some of the advantages I see for having a tuner are:

• I may improve over just using my load development to manage harmonics
• It's tunable fairly easy for different factory or reloaded ammo.
• It can be fine tuned for differences in altitude, humidity, temperature if needed.
• It may save some costs on load development

Are there any gunsmith's that specialize in tuner installations that anyone would recommend? You can PM me if you want.

 

[Radman]

First I watched every youtube video I could find on the subject, then I went out and bought some shaft collars, and couplers that would fit two of my rifles, and began experimenting a little. Lately, I read everything I could find on LRH from posts ranging from 2006 to present, then I searched for more details on the internet in general. I found Varmintal.com which is authored by a gentleman who retired from Lawrence Livermore labs, and spent his whole career running complex structural analysis on steel and other materials using models with time-steps and cells where the model calculates pressures, velocities, harmonics, and all the data 1 step and 1 cell at a time all the way from the ignition at firing down to the end of the barrel. This is called FEA analysis or Finite Element Analysis. He has a fascinating web site with a ton of science behind his conclusions. I understand harmonics because I had to have labs specializing in harmonic vibration on larger rotating compressors and machinery analyze harmonic vibrations which were tearing down multi-million dollar facilities.

Now, I know there are perhaps many on this site who will just say, you don't need a tuner, because if you reload, you can tune the harmonics out of your rifle with bullet seating, and powder selection and velocity/pressure optimization.

But, its clear to me from all the reading that I've done that there are just as many who will say, yes, you can get 70 or 80% there by bullet seating, and powder selection, and velocity/pressure measurement, and glass bedding, free floating, pillar bedding, and having a good stock. But there are just as many who will tell you they went from 0.5 MOA groups to 0.2 MOA groups or from 1 MOA plus groups to .75 MOA groups using a tuner after they did all of the above. It's maybe not critical for hunting in the 100-300 yard range. I usually shoot and tag 3-4 deer per year all from 30 yards to 150 yards max. But for long range hunting and ELR shooting, I would think any improvements in group size would be sort of important? Evidently, a lot more competitive benchrest shooters are using tuners than used to or were back in 2006? I have come to believe they can help improve groups even after good load development.

I'm looking for 1 ragged hole accuracy at 100 yards with all my rifles. So, I am considering buying and having a gun smith install tuners on several of my rifles.

Some of my questions were answered by my reading, and I had good results using my cheapo experiments especially on my .338 Lapua Magnum just using a $25 shaft collar that weighs about 1.8 lbs. It was hard for me to believe that part of my performance issues on MOA with this rifle were harmonics related, because it is a free floated barrel, and it's a big heavy barrel. I started to realize just how much pressure and velocity can affect even a big heavy barrel, and that all rifles have harmonics that have to be managed. My MOA went from around 1 down to 0.5 to .625 range when I installed the 1.8 shaft collar, using the same loads. That's when I knew that this rifle had a harmonics issue, even as big and heavy as it is.

My Lapua is the Savage BA 110 LE law enforcement model which weighs 17 lbs. with a 26 inch bbl. Plus Muzzle break, even with no scope etc. It's not a rifle I plan to carry further than from the car to the benchrest or to a portable benchrest looking out over a 500 or 700 yard long clear cut or wild flat canyon lands with a big view down on the Pecos in Texas. It's a firearm that is generally planned to be fired from a pre set or expedient station, not carried, certainly not in mountains.

Several things I have had on my mind. 1) How much weight is optimum for a barrel tuner, and does the length, and diameter and weight of the barrel have any correlation to that answer? I'm thinking that the 9 oz. to 12 oz. weights used in Harrell's and the EC Tuner may not be enough for a big heavy barrel? Nor may the muzzle brakes they build onto those tuners be sufficient or at least equal to what is already there. Its also clear to me that you can also overdo the weight of the tuner as Varmintal shows that in some of his experiments. How do you decide what is perfect for your rifle without running an FEA analysis? Someone must have some ideas or experience?

Since I have a standard factory Savage muzzle break on my .338 Lapua, what is the best tuner available commercially that incorporated an adequate or optimum break for a large caliber rifle if anyone makes one?

I know both Harrell's and Eric Cortina make tuners that incorporate muzzle breaks, but I need to make sure I get a good one for this rifle, and I don't care about weight vs. really good function.

Because the Savage factory muzzle break is designed with no ports on the bottom, it has more gas escaping straight up which forces the barrel downward too. Is this potentially one of my harmonics problems with the rifle? Is there a better muzzle break design for accuracy?

Some of the advantages I see for having a tuner are:

• I may improve over just using my load development to manage harmonics
• It's tunable fairly easy for different factory or reloaded ammo.
• It can be fine tuned for differences in altitude, humidity, temperature if needed.
• It may save some costs on load development

Are there any gunsmith's that specialize in tuner installations that anyone would recommend? You can PM me if you want.

Very interesting & refreshing read. Thanks. While I cannot answer your questions I agree with you as I have discovered for myself the dramatic effects of harmonics. This is why I stress to friends that wherever you support your weapon during zeroing ALWAYS support it at the same spot when you take the shot! Too, I recently bought a nearly new Remington .243 that someone wanted rid of. The rifle was a pig! Always close but never a cigar. I found that the stock forearm was touching the barrel at several points down the barrel! With a little sanding & repeated checking it now shoots like a laser! Thanks again for a great post!

 

[Rardoin]

I recently had a chance to run a tuner test at the end of a 1000yd match. The three 5 shot groups at 3 tuner settings were shot rapidly (about 3-4 sec between shots) and about 3 minutes between groups/no barrel cooler. Target labelled '0' was the base tuner setting that the load was developed in. The temps were running hotter and I was about 1600 ft ASL where the load was developed about 60ft ASL. The first group shot very good vertical but wide however conditions were quickly switching headwinds so most of that is likely windage. The second group shot about 30% less vertical and tighter horizontal. The next setting showed the load 'blowing up'. This is why I advise shooters to test the tuner and test often/different conditions/repeat testing until a predictable pattern appears; at that point the tuner becomes of great utility. I predicted that the load may shoot the same or a little better on setting '1' (0.001" further away from the muzzle) since the temps were hotter. I also knew that there will be an inflection point where the load would go vertical...and I found it. On what setting would I shoot the match to follow (hypothetically if there was one to follow a few minutes later)??? If I was shooting benchrest I would likely run with setting 1 since I would be rattling off 5-10 shots as fast as I could before conditions changed (much like my test). However since I shoot F-class, which is 20 shots shot over 30 minutes and at least 5-8 seconds between shots and sometimes much longer, I need a tune setting that was not going to blow up if conditions changed during the match. In this case I would twist the tuner between 0 and 1 (or the '1/2' setting). I should be safe there...not the tightest groups possible but well under X-ring of vertical. This match was shot on 0-5pt/V ring ICFRA targets so the .5 moa V ring is like a NRA X-ring.

 

[Rardoin]

Sorry for the obnoxious image sizes. I could not figure out how to reduce them. The lowest shot in group 3 was about 30fps less than the average...a bad load for some reason.

 

[nealm66]

Dang, that's some good shooting. I've always set mine to a bullet/load and left it but I've heard of guys keeping tuner data as part of they're dope.

 

[Veteran]

That's pretty good shooting at 1000 yards, especially with a .308. I understand your process and your logic, it all makes good sense.
Boy was that third group strung out when you changed the tuner. Two questions.

1) Why so low a muzzle velocity at 1700 fps or is this terminal velocity at the target? It does not say. Seems awful low for a .308 at the muzzle though?

2) How much difference was there in your tuning settings between targets 0, 1, and 2, ie, how sensitive was it to the blow up mode?

 

[Veteran]

Dang, that's some good shooting. I've always set mine to a bullet/load and left it but I've heard of guys keeping tuner data as part of they're dope.

I think his main concerns were not only the temperature change but the fact he developed that load at 60 ft. altitude above sea level and his match was up at 1600 feet above sea level. Bound to need to be retuned for the differences in humidity, barametric pressure, and thinner atmosphere. I can sure see why match shooters would find tuners a big help. Better than tinkering with fine tuning a new load everytime you shoot some place different.

 

[Veteran]

It also seems like it would be damned important if you develop a load at a low altitude place like for instance Houston, and then
go hunting in the mountains up in Montana or Wyoming or Alaska. Sure would be easy to retune that load with a barrel tuner than miss an elk at 1000 yards.

 

[Rardoin]

This was not a .308; the target system was set to .308 cal.. I was shooting a 7 Sherman Short mag/190 A-tip at 2740fps mv. The velocities shown are terminal velocity as calculated by the target hub...which are spotty at times but was really close to predicted Vt. I don't have and would not use a tuner for a hunting rifle as I want to develop a load that has a very broad tune window even if it gives up a little precision (which is usually the trade off) as a gun shooting 10" at 1000yds over 20 shots would be effective for hunting but inadequate for winning F-class matches. But, the 10" tune would likely be there in all conditions where a load shooting less than 3" of vertical will need to kept on top of.

 

[GLTaylor]

So, how much movement of the tuner from "0" to "2"?

 

[Rardoin]

So, how much movement of the tuner from "0" to "2"?

0.002" axial movement