I might think that competitors would not want to let that information out as that may be their winning combination?
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Fx 700mm barrel tensioner kit- solution for increase in muzzle crack
- Thread starter Redwolfpaul25
- Start date
I don’t need to copy anybody’s setup to be able to tell if my gun shoots better... I just check it in my back yard. If you don’t experiment you’ll never know.
FX is field testing every product they put out and there are many pro shooters involved in the design and using the tenssioners.
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I have the tensioner system on my M3 and it did make a difference in the accuracy and consistency and eliminated any poi shift.....in my opinion, I think it works best if the small carbon tube is epoxied to the liner as I tried it first without and I could see a difference after I epoxied it. The thing is, none of it is tightened down to the point that the barrel housing is being stretched....the barrel housing tensioner clamp screws are tightened to 20 inch pounds and the nut for the outer carbon fiber tube is tightened just enough to stiffen everything together....I guess someone could go overboard on over tightening everything, but it's definitely not required. The one thing that I did take notice to when installing it... is to make sure both ends of the outer carbon fiber tube are perfectly square, I squared them up on the lathe before installing it. I'm very happy with the difference it made on my rifle.... results may vary for others.
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This response makes the most sense to me thus far. I may be playing with semantics here, but what is a bit confusing me is it is being referred to a barrel tensioning system. My interpretation is in reality, it is being used as more of a barrel stiffening system. We are not able to tension this particular barrel system to the point of making a significant increase in barrel vibration frequency and an accompanying significant decrease in magnitude. To do that does indeed require stretching the barrel to an extent. Again, this may just all be the way I am interpreting (or misinterpreting) things and splitting hairs so to speak.
There is a video out there where Tom Costan is explaining, in great detail, some history of commercial firearm barrel tensioning and how/why he built similar functionality into the AAA barrel tensioning system used in guns like the EVO and a gun we do not hear much about anymore, the Slayer. If you look at how a gun is designed and built, IMO Tom's guns make the least amount of compromise around barrel/breech/sighting system stability. At the heart of that is a very robust barrel tensioning and barrel/breech attachment system. This is not intended to start a AAA vs xxxx manufacturer debate, just using AAA guns to point out a very effective implementation of a barrel tensioning system.
I test a lot of mods/changes on my guns, often times results do not vary significantly different across multiple configurations. Sometimes I struggle to translate the actual impact of a change and if the change/mod is worth the effort. There are times when I ultimately realize a series of changes/mods resulted in a bandaid applied on top of a bandaid so to speak....and in some cases, at a later date, I find the clarity needed to rip off those bandaids. An example, currently I am testing a balanced valve in place of a traditional valve. I've flip flopped back and forth between the 2 valves a few times now. Results are so similar between the 2 very different valve systems that I am debating if the balanced valve is truly worth the added complexity. The tuning process is very different, and with the balanced valve I can have more control over the closing cycle. In theory I should be able to achieve greater efficiency by optimizing the closing cycle. Or I may be solving a non-existent problem and creating potential for problems that could not exist prior to the introduction of this modification...... The jury is still out on that one....
Again, this dialogue is helping me to decide if and how to implement a similar system as you all demonstrated here, on another platform which I am intending to use an 700mm fx impact barrel assembly. Thank you.
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I understand exactly what you are talking about....I used to be into the rimfire benchrest game, I started off building my own rifles and ended up being in the rifle building business for a few years...., used mostly Turbo, Stiller and 40X actions....Shilen, Benchmark and Mueller barrels etc. Taught myself over the years how to cast lead laps and properly lap barrels and during that time I really got into the harmonic tuning of barrels and making barrel tuners etc. In my small machining shop, I've literally got several trash cans full of failed experiments that I have machined over the years experimenting with different aspects of tuning barrels. I've got a few that actually made a difference and a lot that was a total waste of time...lol I once took a 1" diameter barrel that was 26" long and after chambering and fitting it to the action and pillar bedding it in the stock, I machined a groove in the barrel just in front of the stock and machined another groove 1" behind the muzzle end, I machined two split rings out of stainless steel 2" diameter and used 4 lengths of steel drill rod threaded on both ends and attached them to the split rings equally spaced around the barrel...it looked like a Gatling gun...lol I could tighten those rods and manipulate the point of impact with that barrel without ever touching the scope...I actually got that barrel shooting very well and it was very consistent but I would never shoot it in a competition as it was just too crazy looking....but, my point in telling all this is...it really didn't take as much pressure as one would think when tightening those rods to change the impact on that barrel, the least little bit of tightening would make a major change at 50 yards on target....In my opinion, that's why I think using this barrel tensioner system on the M3 works without having to tighten it down to the point that the barrel housing is being stretched, I agree that it should be called a barrel stiffener instead of a tensioner.
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I spent many many weeks testing and investigating with the barrel tensioner, shoot thousands of pellets and slugs @ 100 meters BR, and I can confirm for my setup that it made a difference in POI and grouping.
But not for a better.
The stiffer barrel made the harmonics worst. And with the barrel stiffener outer CF tube I could not use my shroud integrated harmonics tuner.
Also for several months I was shooting with a CF sleeve over the liner, not bonded but a tight fit only (wrapped with teflon tape).
Ended back to floating liners, orings on every 10cm distance on full 700 length, no barrel tensioner tube but the barrel harmonics tuner only. I left the Front Tensioner Block on the gun and tensioning (reasonably) the shroud only.
For my shooting .25 cal up to 41gn slugs this setup works the best for scoring.
This is my FX Impact MK2, .25x700, tuned for ZAN 37gn slugs now, dedicated for BR 100.
But not for a better.
The stiffer barrel made the harmonics worst. And with the barrel stiffener outer CF tube I could not use my shroud integrated harmonics tuner.
Also for several months I was shooting with a CF sleeve over the liner, not bonded but a tight fit only (wrapped with teflon tape).
Ended back to floating liners, orings on every 10cm distance on full 700 length, no barrel tensioner tube but the barrel harmonics tuner only. I left the Front Tensioner Block on the gun and tensioning (reasonably) the shroud only.
For my shooting .25 cal up to 41gn slugs this setup works the best for scoring.
This is my FX Impact MK2, .25x700, tuned for ZAN 37gn slugs now, dedicated for BR 100.
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You can remove the tapered end cap on that shroud by heating with a heat gun and unthreading it and have it machined larger to fit over the outer carbon fiber tube and machine a new larger o-ring groove in it. That's what I did to mine, I'm using the stock shroud over the carbon fiber outer tube.
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Here's what I did to fit the CF harmonic tuner shroud over the CF tensioner sleeve:
This project was done on FX Impact M3 .22Cal 700mm
I use the stock (empty) FX moderator because it works just fine and does not affect accuracy as much as every other moderator I tested.
First thing was to tune the gun properly in its stock configuration and get the best possible groups consistently.
Then I installed the liner carbon fiber sleeve and verified better accuracy with the initial tune. Accuracy was same or slightly better.
Next came the CF barrel tensioner and I found that the tensioning force (by tightening the muzzle nut) affects the tune quite a bit so I played with the tension torque until I got it to a sweet spot where the initial tune was not affected. I marked the nut with a dot so I can easily remove and reinstall it to the same exact position. At this point the barrel wasn't noodling any more and felt much more solid on the action. I left it in the AZ sun for a few hours and there was no POI shift or change to the accuracy. Noise level was unacceptable though...
Next test was to create a solid barrel mass between the liner and the tensioning sleeve. The metal sleeve OD is 14mm and the tensioning CF sleeve ID is 18mm so there is quite a bit of a gap between the two. 14mmx18mm CF sleeve was ordered to fill this gap. the fitment was very tight so no need to epoxy at this point. I used silicone lube to get the sleeves to slide over each other.
The new sleeve was carefully measured to fit perfectly between the action barrel clamp and the tensioning nut so it also became a part of the tensioning system. I cut it and squared it like this
and tightened the tensioning nut to the same spot where it was
Note the black marking on the nut.
Tested the gun again and the tuning was a bit off so I had to retune slightly but now the groups were noticeably smaller!!
I would have left it as is if it wasn't for the noise level that became even higher... very snappy like a 22LR and not back yard friendly any more.
Next step was to fit the FX shroud back on but the conical nut of the original shroud comes with a 14mm ID and no longer fits the now larger barrel @ 20mm OD. I opted for the FX CF harmonic tuner shroud because I wanted to test a tuner anyway and it was also supposed to be quieter.
The conical cap was removed with heat. Here's a photo of both the original shroud and the CF shroud end caps removed. Note the difference...
I designed a new 3D printed end cap to fit the 20mm barrel but I used o-rings instead of adhesive (loctite) for easier maintenance.
Here' a rough plan (not the actual cad file)
and here's the printed cap (courtesy of my friend Yaron) using 2 o-rings inside and 3 outside to snugly and tightly fit the outer shroud and the 20mm barrel.
Fitted with silicone lube
and clears the valve adjusting knob nicely
Gun is super quiet. I can't A/B with a stock M3 but I believe it is quieter.
After tweaking with the harmonic tuner the tune stayed the same but the accuracy in both 50 and 100 is significantly better than stock and I have no more POI issues between different sessions.
This project was done on FX Impact M3 .22Cal 700mm
I use the stock (empty) FX moderator because it works just fine and does not affect accuracy as much as every other moderator I tested.
First thing was to tune the gun properly in its stock configuration and get the best possible groups consistently.
Then I installed the liner carbon fiber sleeve and verified better accuracy with the initial tune. Accuracy was same or slightly better.
Next came the CF barrel tensioner and I found that the tensioning force (by tightening the muzzle nut) affects the tune quite a bit so I played with the tension torque until I got it to a sweet spot where the initial tune was not affected. I marked the nut with a dot so I can easily remove and reinstall it to the same exact position. At this point the barrel wasn't noodling any more and felt much more solid on the action. I left it in the AZ sun for a few hours and there was no POI shift or change to the accuracy. Noise level was unacceptable though...
Next test was to create a solid barrel mass between the liner and the tensioning sleeve. The metal sleeve OD is 14mm and the tensioning CF sleeve ID is 18mm so there is quite a bit of a gap between the two. 14mmx18mm CF sleeve was ordered to fill this gap. the fitment was very tight so no need to epoxy at this point. I used silicone lube to get the sleeves to slide over each other.
The new sleeve was carefully measured to fit perfectly between the action barrel clamp and the tensioning nut so it also became a part of the tensioning system. I cut it and squared it like this
and tightened the tensioning nut to the same spot where it was
Note the black marking on the nut.
Tested the gun again and the tuning was a bit off so I had to retune slightly but now the groups were noticeably smaller!!
I would have left it as is if it wasn't for the noise level that became even higher... very snappy like a 22LR and not back yard friendly any more.
Next step was to fit the FX shroud back on but the conical nut of the original shroud comes with a 14mm ID and no longer fits the now larger barrel @ 20mm OD. I opted for the FX CF harmonic tuner shroud because I wanted to test a tuner anyway and it was also supposed to be quieter.
The conical cap was removed with heat. Here's a photo of both the original shroud and the CF shroud end caps removed. Note the difference...
I designed a new 3D printed end cap to fit the 20mm barrel but I used o-rings instead of adhesive (loctite) for easier maintenance.
Here' a rough plan (not the actual cad file)
and here's the printed cap (courtesy of my friend Yaron) using 2 o-rings inside and 3 outside to snugly and tightly fit the outer shroud and the 20mm barrel.
Fitted with silicone lube
and clears the valve adjusting knob nicely
Gun is super quiet. I can't A/B with a stock M3 but I believe it is quieter.
After tweaking with the harmonic tuner the tune stayed the same but the accuracy in both 50 and 100 is significantly better than stock and I have no more POI issues between different sessions.
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No, I was nervous because it was brand new but i chucked the whole assembly up with most of it in the thru-bore on my spindle and machined it installed on the tube(wrapped carefully with 2" blue painters tape.)
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I initially fitted the tensioner kit with just the inner carbon sleeve and tensioning up the barrel nut as per the norm. The results were terrible. It did help a little with accuracy but POI changes were worse than the STD setup...and that's saying something.
I ended up bonding the FX liner and inner carbon tube permanently to the steel barrel tube. I then got a piece of 25mm OD heavy wall carbon tube, machined some spacers . This assembly was placed over the 20mm carbon tube that comes with the FX Tensioning kit.
Again this was bonded permanently in place . the whole barrel assembly is now effectively one piece.
When i install it i just slide the assembly into the frame until it bottoms on the barrel clamp forward of the reciever....NO tension .
Accuracy is superb and POI impact changes have been eliminated.
The other very important aspect is you can now "Bump" or move the barrel , rough handling or otherwise and the POI doesn't change!!
The original Stock FX barrel setup leaves A LOT to be desired!!
I ended up bonding the FX liner and inner carbon tube permanently to the steel barrel tube. I then got a piece of 25mm OD heavy wall carbon tube, machined some spacers . This assembly was placed over the 20mm carbon tube that comes with the FX Tensioning kit.
Again this was bonded permanently in place . the whole barrel assembly is now effectively one piece.
When i install it i just slide the assembly into the frame until it bottoms on the barrel clamp forward of the reciever....NO tension .
Accuracy is superb and POI impact changes have been eliminated.
The other very important aspect is you can now "Bump" or move the barrel , rough handling or otherwise and the POI doesn't change!!
The original Stock FX barrel setup leaves A LOT to be desired!!
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Just to verify, you said “I ended up bonding the FX liner and inner carbon tube permanently to the steel barrel tube”. Did you epoxy the liner to the carbon sleeve and the sleeve to the metal barrel tube?
Regarding the tensioning sleeve, I found that it acts like a tuner and depending on the tensioning torque can be adjusted to a sweet spot and contribute to the total accuracy. I ended up torquing to a much lower level than I expected. I estimate around 10 inch-pound.
However I didn’t experience poi shifts, but every gun is different. Did you verify the tensioning sleeve ends to be 100% square? Mine were not perfect out of the box.
No doubt, the FX barrel system is weird and takes a lot of maintenance and head scratching.. sometimes I wish it came with a normal solid polygon Walther bbl (-;
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Yes...
Also the above assembly to the 2 other outer carbon tubes.....the original FX tube that comes with the tension kit...and another 25mm piece that i machined along with the spacers i also machined..
This has resulted in a VAST improvement over the flimsy, inconsistent factory setup.
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Won’t happen… FX is making a fortune by making cheap barrels in house and then making even more profit selling us the accessories to fix the problem (-; But I still love that gun.
It is very doable making a real bbl for the Impact. Here’s a YouTube video showing one made and the expected results:
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All great info thank you all for sharing. It gives me a lot to consider in using the system on my Veteran.... It is ironic that I will be placing one of the most cantankerous barrel systems on one of the most stable platforms, but knowing that ahead of time will help manage expectations. Being able to swap twist rates with relative ease/lower cost is the primary reason. 700mm Veteran barrels are not as easy to come by as FX liners... When I find a combination that produces desired results I will likely have Greathouse machine a real barrel with similar specs.
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In case anyone is interested in epoxing the CF liner sleeve to the outer black barrel housing, UAG sells the barrel housing by itself ($29 for the 700mm).
This is a good option if you got multiple liners.
I will follow wooferocu's method and epoxy mine. Will report back with any results.
This is a good option if you got multiple liners.
I will follow wooferocu's method and epoxy mine. Will report back with any results.
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