Fx 700mm barrel tensioner kit- solution for increase in muzzle crack

[6gun]

hello after all the modification of the cap is that I tighten the cf tube with tensioner nut or with the shroud? thnk u

View attachment 330914

That remains, it is how you would attach any moderator or shroud.. Barrel tube> liner nut as usual, slip on cf tube, tighten tensioner nut (female to barrel nut and finishes with a male 1/2-20). You must bore out any shroud tail cap you use to slip over the cf tensioner and the shroud screws on as it normally would, just moved forward a bit (that doesnt matter anyhow since youve machined the shroud tail cap significantly shorter by necessity since youve significantly increased the tail cap inside diameter and likely faced the tailcap nicely) and machined 1 or more oring journals into the cap.

If the assembly is confusing, i highly reccomend against attempting this mod, as your changes to the shroud will be irreversible and fx parts are not cheap. Everything is recoverable but explaining how to make a bushing collar( should you have to try and fix it) is a bit hard without drawing it up for you. The aluminum shroud tail cap is threaded in and easier to work with than the carbon harmonic tuner shroud's epoxied in tail cap. I modified both, using the alminum shroud as my prototype.

 

[6gun]

This is the only modified part. And it made all the difference in noise combined with a dfl ronin at 158 bar plenum pressure. (70ft/lb in 22)

 

[amindz05]

Ok now I start my modification thank you very much

 

[Ca_Varminter]

Well using the standard tuning Shroud as the tension "Nut" for the barrel tension system..
Nothing is modified... Only a piece of 20 x 14mm CF tube is needed...
Also you can control the amount of tension is used.....
By using a 1/2"-28 nut(flange) and a washer.......

Thread the nut and washer on to the Moderator extension
I started at 80 in-lbs..
BTW this actually a bit less than when I was doing by hand!!
To remove the nut, I use a pair of channel-locks to secure the washer and remove the flange nut

 

[6gun]

Well using the standard tuning Shroud as the tension "Nut" for the barrel tension system..
Nothing is modified... Only a piece of 20 x 14mm CF tube is needed...
Also you can control the amount of tension is used.....
By using a 1/2"-28 nut(flange) and a washer.......

Thread the nut and washer on to the Moderator extension
I started at 80 in-lbs..
BTW this actually a bit less than when I was doing by hand!!
To remove the nut, I use a pair of channel-locks to secure the washer and remove the flange nut

I was doing this previously and achieving great results. My issue was the bbl was sensative to being shifted and stayed there till i left it in the sun and then it would shift back. Honestly its the way to go for 95% of people imo, especially if you have a 5 or 600 mm. My 700 had too much leverage for how hard i am on my rifle with a soft backpack case. Not abusive but i do shift the bbl as a varmint gun.

 

[blando]

Hi everybody.

Recently i installed a installed a 700mm fx tension kit onto my .25 M3, not so much to see if i can increase accuracy as its already quite good but moreover to see if i can eliminate POI shift ( jury is still out on that one !).
Obviously removing the fx factory shroud and replacing it with the carbon fibre shroud and jam nut has ment that there is quite a increase in muzzle report as my current tune is pushing 41g slugs at 960fps ( some 80 odd ftlbs) and my 0DB sound mod is not coping very well. Has anyone else experienced this ? Im thinking of putting a carbon fibre tube cut to the appropriate and sliding that over the barrel tension tube to see if that soaks up any of the sound, next will be seeing about a different sound moderator, maybe a donny fl Ronin or something else.

Hi. I bought the tensioner for my m3 700mm .25. Would not work. When I tightened up everything the gun would not zero!!! Pulled the liner so far down and to the right that I didn’t have enoclics to get poi on paper so I just gave up. Anyone else have this issue and is it fixable


Respectfully

Mark

 

[6gun]

Hi. I bought the tensioner for my m3 700mm .25. Would not work. When I tightened up everything the gun would not zero!!! Pulled the liner so far down and to the right that I didn’t have enoclics to get poi on paper so I just gave up. Anyone else have this issue and is it fixable


Respectfully

Mark

Technically its fixable, checking that the ends of the carbon are square and your action block is square will help. First thing i would try is silicone oil on the ends to make sure it can move or settle into position and mark where it is now and use any directional nature to my advantage and re-clock the carbon tension tube. Mine if bumped would poi shift and sit there only to eventually settle back in another day. After a little silicone it no longer retains a poi shift and im grabbing my gun by the barrel fairly often.
700mm 22
Carbon liner stiffner
Carbon tensioner
Carbon harmonic shroud (modified to fit)
Donny ronin.
Shes heavy

 

[blando]

Technically its fixable, checking that the ends of the carbon are square and your action block is square will help. First thing i would try is silicone oil on the ends to make sure it can move or settle into position and mark where it is now and use any directional nature to my advantage and re-clock the carbon tension tube. Mine if bumped would poi shift and sit there only to eventually settle back in another day. After a little silicone it no longer retains a poi shift and im grabbing my gun by the barrel fairly often.
700mm 22
Carbon liner stiffner
Carbon tensioner
Carbon harmonic shroud (modified to fit)
Donny ronin.
Shes heavy

Thank you!! How do u make sure all is square. Carbon tube and block. Thank you

Mark

 

[6gun]

Thank you!! How do u make sure all is square. Carbon tube and block. Thank you

Mark

A quality square (no framing speed squares) and some dyechem or sharpie marker. Sharpee the end and use the square to mar the sharpee off, where the ink remains would be the low spots. A dial indicator and a lathe is ideal. Looking carefully for light may suffice. It gets pretty esoteric and high precision. Silicone and clocking the tensioner to your advantage is likely the best course of action to explore. Or call wherever you bought it from and try to get a true piece of carbon tube.

The really dirty secret i found is home brew spacer collars to use the factory shroud to tension are nearly as good as the carbon tensioner in my experience. Not identical but for a 2 dollar part it does a better job for the price. I realize the tools and skills i have arent super common, but after buying a tensioner and tungsten hammer i spun out a bunch of tensioners on the lathe and huma style "wide open" pellet probes and tungsten loaded hammers of custom weight for my buddies and saved them the time and money. A harmonic tuner helps dial around some minor shift too.

 

[blando]

A quality square (no framing speed squares) and some dyechem or sharpie marker. Sharpee the end and use the square to mar the sharpee off, where the ink remains would be the low spots. A dial indicator and a lathe is ideal. Looking carefully for light may suffice. It gets pretty esoteric and high precision. Silicone and clocking the tensioner to your advantage is likely the best course of action to explore. Or call wherever you bought it from and try to get a true piece of carbon tube.

The really dirty secret i found is home brew spacer collars to use the factory shroud to tension are nearly as good as the carbon tensioner in my experience. Not identical but for a 2 dollar part it does a better job for the price. I realize the tools and skills i have arent super common, but after buying a tensioner and tungsten hammer i spun out a bunch of tensioners on the lathe and huma style "wide open" pellet probes and tungsten loaded hammers of custom weight for my buddies and saved them the time and money. A harmonic tuner helps dial around some minor shift too.

Thank you so much!!!

Best regards

 

[blando]

How do u cut and use the brew caps?? Where can you buy them? Where or how do you apply that modification?? Sorry your knowledge is way above this old boy!

Thank you so much!!!

Best regards

 

[preeb]

Any success removing the conical rear cap off the CF shroud cleanly?
I assume it is not threaded but rather glued/epoxied.

 

[DBlue]

I installed the .700 tensioner kit on my .25 M3, JB welded the carbon tube on the liner and removed the rear cone from the stock shroud with a heat gun and machined it with a new o ring groove and new o ring to fit the carbon fiber outer tube. I do not see any need for adding another screw in the rear block as my M3 has the tensioner clamp on the front of the receiver and with it clamped down with the proper torque there is no way the barrel is going to move when tensioned. It made a hell of a difference in the way my gun shoots now....

 

[6gun]

I installed the .700 tensioner kit on my .25 M3, JB welded the carbon tube on the liner and removed the rear cone from the stock shroud with a heat gun and machined it with a new o ring groove and new o ring to fit the carbon fiber outer tube. I do not see any need for adding another screw in the rear block as my M3 has the tensioner clamp on the front of the receiver and with it clamped down with the proper torque there is no way the barrel is going to move when tensioned. It made a hell of a difference in the way my gun shoots now....

View attachment 387688

How was your change in muzzle report using the aluminum shroud?

 

[6gun]

Any success removing the conical rear cap off the CF shroud cleanly?
I assume it is not threaded but rather glued/epoxied.

In the carbon shroud yes, threaded and liberal use of loctite on the aluminum.

 

[DBlue]

How was your change in muzzle report using the aluminum shroud?

It works really well....with the Huggett Astille moderator it's like mouse fart quiet....

 

[preeb]

In the carbon shroud yes, threaded and liberal use of loctite on the aluminum.

I assumed it was epoxied since you wrote:
“The aluminum shroud tail cap is threaded in and easier to work with than the carbon harmonic tuner shroud's epoxied in tail cap. I modified both, using the alminum shroud as my prototype.”
Did you remove the CF shroud tail piece with heat? Same way as the stock aluminum shroud is removed?

 

[mackeral5]

Tensioning of a liner style barrel is a bit confusing to me. The housing, which is what is being tensioned/stretched. Prior to being tensioned, the liner is in slight compression created by tightening the 1/2-20 threaded piece at the muzzle end. I say slight compression as their is only a small amount of torque that can be applied to those wrench flats and 20 pitch threads do not offer much mechanical advantage. When you tension the outer sleeve/housing, the outer sleeve stretches slightly. Does this not relieve some of the compression on the liner, potentially leaving it loose and potentially vibrating/buzzing in the housing?

Please forgive my ignorance here, I do not have any first hand experience in this area.

 

[preeb]

Tensioning of a liner style barrel is a bit confusing to me. The housing, which is what is being tensioned/stretched. Prior to being tensioned, the liner is in slight compression created by tightening the 1/2-20 threaded piece at the muzzle end. I say slight compression as their is only a small amount of torque that can be applied to those wrench flats and 20 pitch threads do not offer much mechanical advantage. When you tension the outer sleeve/housing, the outer sleeve stretches slightly. Does this not relieve some of the compression on the liner, potentially leaving it loose and potentially vibrating/buzzing in the housing?

Please forgive my ignorance here, I do not have any first hand experience in this area.

The barrel includes all the sections that surround the projectile as it is being propelled.
The more rigid the entire barrel mass is, the less it is susceptible to whipping or harmonize with the energy of the moving projectile.
It is advisable to stiffen the liner by removing any flexibility. The stock liner is suspended in the inner metal sleeve by o-rings that allow it to whip to a certain degree which can be minimized by replacing the o-rings with a solid carbon fibre liner sleeve. The next step is to further stiffen those 3 layers by adding tension to the metal sleeve that holds the other 2 layers.
The FX barrel tensioner does 3 things:
1. Creates tension to stiffen the inner 3 layers mass
2. Adds a 4th layer of extra mass
3. Tightens the barrel against the action to minimize flexibility and poi shifts
You can always take extra steps and remove any voids by adding a 5th layer between the barrel tensioner cf sleeve and the metal sleave by adding an additional cf sleeve (see photo).
All the above made my M3 more accurate as long as I do my part.
The noise level will become much higher and the FX external shroud will be needed to suppress it.
The shroud conical nut will need to be resized for the larger diameter of the tensioner sleeve.
I used the fx harmonic tuner cf shroud and the gun is very quiet. Plus… I use the tuner for that final adjustment to pull the groups even tighter.
At this point, my M3 with weighted pallets is way more accurate that me (-;

 

[mackeral5]

Thanks for that detailed response. Can we name any competitive shooters, shooting guns with the FX liner system, who consistently perform well using a tensioned FX liner barrel system?

The reason I ask this is I do not recall seeing similar systems on guns in videos of the various competitions we see here on the forum from time to time. If it were robust/reliable/stable, I would expect to see competitive shooters using and recommending these systems.

I ask these questions sincerely as I have the parts to tension, but the more I look at them the more I question the robustness of that system. Maybe tensioning a stiff shroud, tightly around the current system, allowing the current system to expand/contract,while damping vibration but I do not see how stretching a housing that is holding a liner under compression is going to contribute to consistency. Consistency as in POI doesn't shift when the gun sat in the sun and heated up, etc.

Thanks for entertaining these thought processes.