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This may sound like a strange questions but could you tune a barrel using the moderator. 

My thoughts are that a tuner is basically a weight that can be adjusted by sometimes a very small amount to improve barrel harmonics so could you do the same with a moderator using different thickness washers as spacers or as usual am I living in cuckoo land.

I have a jet z compact mod

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I've had the same thought myself. I 'spose the limiting factor is how far it has to be moved and whether there's sufficient thread left for it to be solid and safe.

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I suppose it could work. Rather than using washers, barrel tuners use nylon tipped grub screws to set the position. I suppose that you could have your Jet-Z retrofitted with one of the spigot mount options and then have the spigot drilled and tapped for the grub screws, but this sounds like an awful lot of bother to go to.

However, if you look at the the EC tuners sold by Erik Cortina, these are designed specifically so that they can be fitted behind a muzzle brake or moderator.

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1 hour ago, Mark II said:

This may sound like a strange questions but could you tune a barrel using the moderator. 

My thoughts are that a tuner is basically a weight that can be adjusted by sometimes a very small amount to improve barrel harmonics so could you do the same with a moderator using different thickness washers as spacers or as usual am I living in cuckoo land.

I have a jet z compact mod

Yes, I think you could with a range of washers of different thicknesses. It might be a bit fiddly to tune.

Regards 

JCS

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Just use a threaded collar, similar to self timed muzzle brakes.  Just turn it a full rotation and then lock it down.  Adjust as necessary until you find the right amount.  David Tubbs talked about this for muzzle brakes as well; adjusting them to change where/when the expansion chamber receives the gas.  I'd imagine the same would hold true for supressors/moderators.

 

https://www.americanprecisionarms.com/products/gen-2-little-stripey deckchair-muzzle-brake

 

DSC_4188_copy_copy_3d904588-3634-4e31-a2

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In my experience, and I hasten to add, only with .22lr, once you have found the "near enough" setting, only small amounts of movement are then needed for fine tuning. There also seems to be several different approaches, a heavier weight a couple of inches back from the muzzle or a lighter weight in front of the muzzle that try and either produce a null point at the muzzle or set for a velocity compensating tune. Then there are the  "limbsaver" barrel dampener type systems.
Personally I think .22lr is where the advantage is to be had - With centrefire we can infinitely tune the load to suit the barrel, with rimfire you need to tune the barrel to suite the ammunition.

This is my experimental adjustable tuner between the barrel and the moderator.

mTFeRNll.jpg?1vM0esUxl.png

9KozCA8l.png?5

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3 hours ago, Mark II said:

This may sound like a strange questions but could you tune a barrel using the moderator. 

 

No, its way too heavy.

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9 hours ago, Big Al said:

No, its way too heavy.

Surely depends how short and stiff your barrel is. This one's got lead wheel weights strapped all round it.

ot82dGIm.png?1

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Thanks for replies I think I will give some  shim washers a try, could be a fun experiment 

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10 hours ago, 1066 said:

Surely depends how short and stiff your barrel is. This one's got lead wheel weights strapped all round it.

ot82dGIm.png?1

Just because there is a picture of a guy online like that doesnt mean it works, even the smallest of movements on something like that will give crazy POI shifts, try it and see for yourself. I said what I said to save the OP wasting time with a moderators and based on my own experiences/testing. I would say that thing in the picture was probably a barrel dampener that wasn't intended to be moved like a tuner. People played with that concept with the aim of trying to dampen down the harmonics and make the nodes bigger, it worked but it made guns too heavy to quality for the LV category so wasnt that popular.

The most popular tuners on the market today are in the 3oz-6oz range and even they can be too much on a long slim barrel. One of the best tuners out there for the short/stiff 6PPC benchrest barrels weighs 3.5oz

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Have you tried the limbsaver rubber thing as I would like to use the  moderator with it 

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10 minutes ago, Mark II said:

Have you tried the limbsaver rubber thing as I would like to use the  moderator with it 

A barrel tuner needs to be able to make precise and repeatable movements, the Limbsaver thing doesnt offer that.

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Mark2

lots of different things out there, I’ve seen the Limbsave put in barrels and moved about, and groups of O seal at different locations on barrels while trying to play with harmonics.

With BPCR,s you can put talc along the top of the barrel and ‘ring it’ to determine where to rest on your cross sticks.

Do not think you can categorically say one thing is better than another as a lot of stuff out there is anecdotal. As Al points out sometimes what can be tried is limited by a class restriction. Believe when folks went over to heavy adjustable ladders on TR foresight’s they saw a difference - but that was rumoured 🤔

Have a play, nothing to loose. I can say that a 22rf does benefit by putting ‘something on its nose’ that can be adjusted

C37B21FC-F468-4EF2-87C5-CBE87DCA635A.jpeg.2a57cb725b226b8c4e21a221e444137a.jpeg

Joe Myers gun with Limbsaver and heavy adjustable tuner, think he is current 22rf. Record holder

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10 minutes ago, Big Al said:

A barrel tuner needs to be able to make precise and repeatable movements, the Limbsaver thing doesnt offer that.

I didn't think it would be up to the task. 

Is there one where you can still use the moderator and the barrel doesn't need to be machined

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4 minutes ago, terryh said:

Mark2

lots of different things out there, I’ve seen the Limbsave put in barrels and moved about, and groups of O seal at different locations on barrels while trying to play with harmonics.

With BPCR,s you can put talc along the top of the barrel and ‘ring it’ to determine where to rest on your cross sticks.

Do not think you can categorically say one thing is better than another as a lot of stuff out there is anecdotal. As Al points out sometimes what can be tried is limited by a class restriction. Believe when folks went over to heavy adjustable ladders on TR foresight’s they saw a difference - but that was rumoured 🤔

Have a play, nothing to loose. I can say that a 22rf does benefit by putting ‘something on its nose’ that can be adjusted

C37B21FC-F468-4EF2-87C5-CBE87DCA635A.jpeg.2a57cb725b226b8c4e21a221e444137a.jpeg

Joe Myers gun with Limbsaver and heavy adjustable tuner, think he is current 22rf. Record holder

That is one beast of a rifle 

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1 hour ago, Big Al said:

A barrel tuner needs to be able to make precise and repeatable movements, the Limbsaver thing doesnt offer that.

I think the limbsaver is a damper, rather than a tuner (?)

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45 minutes ago, terryh said:

 

C37B21FC-F468-4EF2-87C5-CBE87DCA635A.jpeg.2a57cb725b226b8c4e21a221e444137a.jpeg

Joe Myers gun with Limbsaver and heavy adjustable tuner, think he is current 22rf. Record holder

I have no experience of rimfire barrel tuners so if this guy is using something this heavy and adjustable and is a record holder then clearly they must work on rimfires.

I imagine the harmonics must be very different to a centerfire case when you consider the pressure differences. 

 

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5 minutes ago, brown dog said:

I think the limbsaver is a damper, rather than a tuner (?)

Yes, that would make sense. Ive seen it touted many times as a barrel tuner but without repeatable fine adjustment it couldn't be.

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I had a Google to try and find some proper theory on what these tuners are doing- couldn't find anything other than mumbo jumbo by calfee - no doubt they work, but I'm not sure I understand precisely what effect they have on the harmonics. 

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Surely the issue is harmonic resonance or more precisely the desire to tune away from resonance but in a fixed and repeatable way.  Hit any object and it will transmit the energy through a wave either longitudinally or transversely, the wave energy being dissipated into sound or heat by internal friction or interference waves.  A bell resonates true because it's tuned to re-enforce the fundamental frequency.  I would think a barrel is mis-tuned to interfere and damp out rather than tuned to a resonant harmonic.

We used a shock-pulse instrument to excite and then 'listen' to vibrations in a structure to ascertain the resonant frequency and harmonics allowing us to damp out or adjust away from any excitation input (eg a motor making an enclosure vibrate to bits).  I wonder if it was practical to monitor a rifle barrel and look for harmonic nodes that equate to the barrel's fundamental frequency?

Probably best to just test and suck it and see?  Cheaper.

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17 minutes ago, brown dog said:

I had a Google to try and find some proper theory on what these tuners are doing- couldn't find anything other than mumbo jumbo by calfee - no doubt they work, but I'm not sure I understand precisely what effect they have on the harmonics. 

We dont really need to understand, so long as they allow us to tune a load does it really matter if we understand whats happening?

Ive done lots of tuner testing and I think I know now what I need to know to get the best from them, even if I dont fully understand the physics.

Below is a test I did a couple of years ago bringing a random powder charge into tune, I then verified it by continuing to shoot small groups at the same tuner setting. The last row shows me taking the barrel out and then back in again. 

 

Screen Shot 2020-11-18 at 22.28.50.png

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12 minutes ago, brown dog said:

I had a Google to try and find some proper theory on what these tuners are doing- couldn't find anything other than mumbo jumbo by calfee - no doubt they work, but I'm not sure I understand precisely what effect they have on the harmonics. 

You might find these links interesting BD. Barrel tuners are very much a rimfire thing, They seem to have been introduced by a benchrest rifle builder in the US in the early 90's by a chap called Bill Calfee. This chaps rifles have won more national and world rimfire BR records than all the others put together. His early tuners were mostly in the 8-10 oz range. Since that time the move has steadily been to move away from, what we might think of as "target rifle" barrels, to much thinner whippy barrels with lighter tuners. 

http://www.geoffrey-kolbe.com/articles/rimfire_accuracy/tuning_a_barrel.htm

https://www.varmintal.com/atune.htm

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Think this whole subject is very interesting 🤔. There is a bit of info out there if you dig. 


As PbG notesthis sort of thing (‘vibrations’) are taken into consideration and engineered out ( eg Helmholtz resonator, spiral flutes on top of chimneys etc) when it’s missed then bad things can happen - the classic Tacoma bridge failure.

What is actually going on in a rifle thought? We all focus on the ‘snake’ and moving this up and down the barrels length, but there is (I believe) a bulge wave, torquing ( where the barrel is barley twisting). How do we tweak these?

But as per Al’s comment , does the theory really matter at our level ( it’s only a game after all) so long as we see some results from our efforts. Caveat - it is nice to play though 😎.

T

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12 hours ago, 1066 said:

You might find these links interesting BD. Barrel tuners are very much a rimfire thing, They seem to have been introduced by a benchrest rifle builder in the US in the early 90's by a chap called Bill Calfee. This chaps rifles have won more national and world rimfire BR records than all the others put together. His early tuners were mostly in the 8-10 oz range. Since that time the move has steadily been to move away from, what we might think of as "target rifle" barrels, to much thinner whippy barrels with lighter tuners. 

http://www.geoffrey-kolbe.com/articles/rimfire_accuracy/tuning_a_barrel.htm

https://www.varmintal.com/atune.htm

The first link is an excellent if somewhat technical read.  I note  the quote:  "It should be noted that Calfee's theories have absolutely no basis in fact and are mathematically untenable. But that does not stop it being the most quoted work in the popular press on barrel vibrations and the tuning of barrels."    Pretty much as Brown Dog described earlier.

It seems to me that it's pretty common in shooting that someone stumbles onto an idea or method and gets results by experimenting (which is laudable) but then tries to back-engineer an explanation without either sufficient knowledge or scientific experimentation.  Unfortunately that's then taken up by a community of non-experts and becomes dogma.  Like many of the most favoured load development techniques (IMHO of course) lacking in any kind of statistical rigour, drawing conclusions from way to small data samples and uncontrolled variables.

 

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PbG

you are correct, a lot of the ‘gospel’ is now being challenged- especially in the 22rf world ( but you’d be called a heretic in some circles 😂)

22rf twist has always been around the 1:16 mark and the ‘no point in having barrels longer than 16” as the bullet’s slowing down’ statement when considering performance- as if velocity was ‘it’

With more focus on 22rf past the 50 (100) yard mark then this dogma appears to be faulty. Interesting times.

Your observation that what you ( or anyone) does is what ‘they’ do. If it works for them then what’s wrong in that? This is why I’ll always caveat with ‘this is what I do but I’m not saying It’s right’ 😉

but I’m always open to suggestions, you can put your own filter on anything new.

T

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