Barrel Tuners (not rimfire)

[Tony Z]

Hi Rod.
Pros are that the accuracy window in 99% of barrels is greatly extended. In some cases there is no bad accuracy load where every load shoots well. Bullet impact of differing weight or brand of bullets is closer at short range but of course due to BCs they separate at longer ranges. The biggest advantage in the case of 1K BR is the greatly extended string of shots that don't drift POI or group size. Not commonly known but i have seen JR shoot 15 sighters and then run a ten shot record with no detriment to POI or group. That was with his 30 Redneck and 77 grains of VV560.

Cons are few but the main one is it is a giant fuck to swap out barrels. The barrel channel has to be the width of the tube and parallel at 40mm plus depending on tube choice. Weight can be an issue if you go with a hefty barrel plus tube plus retainer ring and barrel nut. Finding the right extruded tubes these days is another fuck. The sizes are not what they were and the dimensions can be somewhat erratic in wall thickness.

Tubes are nothing like tuners. Just fit and shoot. Tuners, with a formula or not, will not stay in tune when DA alters from the morning to afternoon. A tube because it is under tension is a structural device and seems to have no characteristic that can be attributed to any harmonic theory. The larger the diameter of tube used the more stable everything gets with the limiting factor being the receiver. The major flaw i see is everyone tries to re-invent the wheel through the use of springs and or tube fillers in the belief that the tube will fail as the barrel heats. The barrel as long as there is tension will do what it is supposed to do. Springs etc only fuck it up. The yanks tried several stress relieving methods on the barrel nut and all failed due to shifting POI. Some were very elaborate but all failed.
Many records have been shot using tensioned barrels but surprisingly few have seen use in other forms of competition besides 1KBR. Mainly because people fuck with the method.
One method i tried a few years ago was a barrel nut that was also a brake where it was inclosed inside the tube and had the same effect of improving accuracy without the muzzle blast of an external brake. Very effective at reducing recoil by diverting gas up into the tube and out the ports once the bullet has long gone. If i ever do another LG that is exactly how i will do it. I have little time for open brakes on my rifles.

[DSD]

One method i tried a few years ago was a barrel nut that was also a brake where it was inclosed inside the tube and had the same effect of improving accuracy without the muzzle blast of an external brake. Very effective at reducing recoil by diverting gas up into the tube and out the ports once the bullet has long gone.

Lucky you live in North Queensland, this theory would probably be enough to get you into trouble as a suppressor in our southern states

[justjeff]

Rod,

I will be able to move the barrel in the block to find the best tune, then I will build a proper stock to suit. Interesting, my second 50mm barrel is here now, so I can get a tune for it too. That will give me a tune for 200 to 210 in one barrel, and a tune for 187 - 200 in the other.

Jeff

[RDavies]

Rod,

I will be able to move the barrel in the block to find the best tune, then I will build a proper stock to suit. Interesting, my second 50mm barrel is here now, so I can get a tune for it too. That will give me a tune for 200 to 210 in one barrel, and a tune for 187 - 200 in the other.

Jeff

A 50mm diameter barrel!! Wow, I gotta see that. Do you have any pics of your current 2" diameter barrel?

[RDavies]

One method i tried a few years ago was a barrel nut that was also a brake where it was inclosed inside the tube and had the same effect of improving accuracy without the muzzle blast of an external brake. Very effective at reducing recoil by diverting gas up into the tube and out the ports once the bullet has long gone. If i ever do another LG that is exactly how i will do it. I have little time for open brakes on my rifles.

Sounds like a great idea. I wouldn't mind trying something like this one day. I absolutely love the reduced recoil of brakes (I just dropped in another 6 Dasher barrel to LRP to have a brake fitted yesterday), but wouldn't mind a quieter version like you made.

[albow]

Hi Rod

What type of brake you having fitted?

[RDavies]

Hi Rod

What type of brake you having fitted?

It is a RAS tuner brake. One of the radial pepper shaker type brakes with a tuner sleeve on it.

[Tony Z]

Oh how uncool Rod!!. I thought you would have had something like a T3 or something with breaching spikes for the odd rabbit that resists arrest.

[RDavies]

Oh how uncool Rod!!. I thought you would have had something like a T3 or something with breaching spikes for the odd rabbit that resists arrest.

Breaching spikes, now that is an idea. When I have had a magnetospeed beyonet on the end I have had the erresistable urge to jump over the trench and charge, but the breaching spikes are so much more practical.

[Tony Z]

The last two weekends i have tried two methods of using a tuner. One with incremental adjustment to find sweet spots. The second using the Rx formula for the 7th, 9th, 17th, 19th and 21st harmonic. Long story short the rifle was fitted with a plane Jane 308 match chambered barrel. Load of 46 grains of 2208 and 155 Dyers in Lap cases shot into 5/8s inch at 200 yards. Tuner fitted then dialed or set to the harmonic length. At no time did any setting better the bare barrel for consistency. Some follow up groups were horrific if they were shot in short succession. Yes i could set the tuner to deviate or converge bullets with differing powder charges (velocity).
When a promising setting was found at no time would the result repeat.
Twenty years ago i did this on a rifle and after all that time the conclusion is the same. Barrels, especially stainless barrels, lengthen with heat and do so quite considerably. You do not need to be a rocket scientist to work out that an adjustable device that tunes to a harmonic length cannot compensate for heat expansion. A rimfire gets away with it because they simply do not produce enough heat, thus expansion to create an issue. I am convinced tuners are as unpredictable as a dyke in menopause. A damper as per Brad's method is more likely to keep the slinger in tighter. Stretchers tubes in my opinion are still the most overlooked and underrated device yet have multiple records to their name in 1K.
Given what i have tried to do, a short stout barrel firing minimal rounds of a few sighters plus 5 record may be another story. Long barrels and long strings with 10 for record, best of luck with it.

[Tony Z]

Seven shot group from a clean cold bare barrel at 200 yards. As pointed out in the previous post, at no time was a tuner setting found to shoot consistently. The first group would be good but as the heat transferred through the barrel steel, successive groups became erratic. What i mean by erratic is the groups would expand to about 3/4 MOA when strings approached 15 shots or more. OK for a pig gun but 1/2 MOA too large for what i want to do. The 20th shot has to go where the first went. Anything less is not acceptable for 600 IBS. Remove the tuner and the barrel shot tight and to original POI thus dismissing any thought there were other external factors.

This week i will fit a tube and shoot some long strings next weekend. Good bad or otherwise i will post the results.

Some of you may recognise the HG as Jeff H's old gun i did the sleeved action for. You will also see i have attacked the alloy stock in the mill to make it more user friendly for me with whatever barrel it ends up with at Narromine later this year. It won't be fitted with a tuner.

[Tony Z]

Well i shot the HG 308 with the tube today. Unlike the previous two weekends where i had pretty good conditions at 200 yards to test with the tuners, today was dreadful with strong winds and terrible mirage that had me shooting on 15x magnification to get a steady sight picture. Long story short, the 6 groups fired with the tube fitted were smaller than the best group with the tuner. The last group being the smallest at 0.400" simply because i got a feel for the conditions. No flags were used with the tuner tests so to keep it consistent there were no flags used today. Just read the boil as we all do up here this time of year.
The real downside was the numerous ricochets through my target from the far left bench where i was on the far right. Safest location was behind his target. I'll be fucked to know how a bullet shot at a target at 100 yards can do a 45 degree turn after hitting the ground and form a group on my target a further 100 yards downrange. It takes a special sort of stupid to do that. His target was clean but everyone elses looked like a grenade strike. FMD.
Anyway i digress. The point is once again after 20 something years the tuner is in the trade waste bin and the tube, thanks to JeffH for having a surplus piece, has proved once again that the structural beam construction has a very positive effect on groups if done correctly and in the simplest form.
But the story does not end there. For shits and giggles later in the day i was able to get out to 300 yards to test 175 SMKs with 43 grains of Re15 which is a replication of the current M118 load used in the USMC M40s. A load i have used frequently over the years in various rifles like my 5R. Both groups were sub inch with one potentially sub half inch if dickhead organic component hadn't missed a drop off in wind. So good in fact i am going to run this at our next 600 IBS match.

My overall findings are this. Yes a tuner can alter things and can do it dramatically. In small numbers of rounds fired, preferably with a smaller cartridge, i believe it can be very effective. What i don't like is the current thought process by some to get a tune with a load. Lock the tuner then set about getting the best load using conventional load development methods. Then adjusting plus on cold temps and minus on hot humid days. ie when the the barrel shrinks you lengthen it, then when it lengthens you shorten it effectively. This has merit for short range group shooting with short stout barrels. For long strings using very powerful cartridges, and long barrels this is flawed. There is no way i could foresee a situation where it was possible to sit there and turn the tuner to compensate for atmospherics and be 100% correct in doing it. As one guy stated on accurateshooter, to do so he wore the barrel out, thus relegating the tuner to the bin. My exact thoughts.
Essentially i can create a situation where i can cause a tuner to fail by simply firing 10 shots, then fire 5 for group and it will fail. The reason i bring this up is that for 1K in dreadful conditions, 10 sighters in a 10 minute sighter period is easily done, then followed by 10 record and you are screwed. With 2 consecutive targets shot under 600 IBS rules with sighters and record shots, you are screwed.
The tube does not do this walking or group expansion crap. As long as it stays tight, it works and keeps shots tight and to POI. To prevent a tube coming loose and that will really send things haywire, all that needs doing is fire 10 shots, allow the heat to move through the barrel and achieve maximum length, then tighten the tube and you're good to go. If you crush the tube, you fucked up because you must use T7 tensile tube. To get it apart, repeat the above because you may never get it apart cold without a 9 inch cutoff wheel. Don't fill the void in the tube with anything like some well known BR shooters did some years ago. Don't fit elaborate jacking bolts to the muzzle like some well known BR shooters did some years ago. Dont fit springs anywhere like some well known BR shooters did years ago. KISS

If anyone wants to try the tuner for themselves, i have a lock ring and two tuner bodies for multiple harmonic lengths. I will give them to you for free, you pay the post. Thread is 32mm x 1.5mm pitch. The condition of sale is post your findings. Good bad or otherwise.

[Brad Y]

Never had that issue with a tuner. I lie. One barrel did. But it wouldn’t group with anything I tried and became a failed experiment that I wont repeat again. Next barrel different maker same reamer and brass and components was a hammer. Barrels will be barrels. Rod Davies has done a lot of work with them. I have seen his rifles shoot. Wouldn’t stand in front of one out to 2000 yards. The last couple that I have done were a complete success. As well. Have just got out of shooting sports for a bit and going to concentrate on wind coaching and some background work but when I get back into it, I will be back running barrels with tuners.

Remember we predominantly shoot for score off a prone position- not for group. I will say the tightest group I have ever shot at 1kBR was with a barrel that didn’t have a tuner. Might set up the next 1kBR barrel without one first, or try that tube thingy if I can find some tube that is semi decent.

[Tony Z]

Brad is it tuner as in adjustable, or damper as in fixed weight?

[Brad Y]

Adjustable mate. Set up at long range, adjust load for best sd and shape possible with powder, seating depth and primer - all with tuner at 0. Then move it out a couple of marks at a time is what I have done for f class. Can usually see where it tightens up. Need to do lots of shooting in different weather conditions to know when to go in and out. My previous 7saum had an es of 6 over 10 shots, sd was 2 or 3. Statistically it wasn’t much but indicated to test there. Once I had it shooting decent, the tuner tightened things right up vertically that bit more. Then I sold it to fund building a back yard on the new house