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FX barrel tensioner

Xono

Member
Jun 13, 2025
19
5
Hello, I currently have a FX Impact M4 and was thinking of getting a FX barrel tensioner kit for looks mainly. I already use a Saber Tactical top rail and was wondering if there will be fitment issues. Also, I'm using a DonnyFL Yokozuna moderator and was hoping I could still use it with the tensioner kit.

Lastly, anyone with experience kindly chime in if it's more trouble than its worth.

TIA
 
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The tensioner block may not jive with the trigger block of the M4 iirc. I have one on my m3. I might suggest the carbon harmonic shroud . They look good but add length and weight, which wasn't for me on a 700mm at the time. The tensioner significantly changes the barrel harmonics tendencies too. If you're not doing high power slugs with an abnoxious shot sequence, I might steer people away from it unless they're suffering barrel whip.

Attached Pic was a remachined carbon shroud over carbon tensioner. The carbon shroud does a great job with noise absorption too. Mines an m3 and I know the tension kit fits that architecture.

20241030_170736.jpg
 
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Hi there, in my opinion having some kind of tensioner is worth the effort on a liner style FX. It has helped me a lot with poi shifting. Be warned though by removing the factory shroud you will increase the noise level. You can still run a moderator though since the tensioner has the correct adapter up front.
The yokozuna minus 1 baffle section was equal to the carbon shroud and a ronin for noise reduction. Mines 75 fpe 22. I run just the yoko and a tenisoner now and it's quiet.
 
The yokozuna minus 1 baffle section was equal to the carbon shroud and a ronin for noise reduction. Mines 75 fpe 22. I run just the yoko and a tenisoner now and it's quiet.
The new Donnys are a better design clearly, but comparing apples to apples losing the shroud will always be louder. I will probably have to figure out a way to try a yokozuna at some point.
 
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The tensioner block may not jive with the trigger block of the M4 iirc. I have one on my m3. I might suggest the carbon harmonic shroud . They look good but add length and weight, which wasn't for me on a 700mm at the time. The tensioner significantly changes the barrel harmonics tendencies too. If you're not doing high power slugs with an abnoxious shot sequence, I might steer people away from it unless they're suffering barrel whip.

Attached Pic was a remachined carbon shroud over carbon tensioner. The carbon shroud does a great job with noise absorption too. Mines an m3 and I know the tension kit fits that architecture.

View attachment 580168
Love what you have done to your M3. Where can I take a look at this carbon shroud?
 
Tensioning is a double edged sword. Especially with a FX because you aren’t really tensioning a solid piece of steel. And even when you do tension a solid steel barrel, you have to do it properly. Most guys that tension a FX barrel and feel it was successful, might be walking a fine line. I started tensioning Impact barrels back in 2020 and noticed some positives and some negatives as my process evolved. Two standouts were temperature sensitivity and the width of an accuracy node. I finally switched to real barrels on two of my Impacts and the one with a modified FX barrel on it is no longer tensioned.
 
Love what you have done to your M3. Where can I take a look at this carbon shroud?
Utah air or anywhere that sells fx accessories. They usually list it as "carbon harmonic tuning shroud" the harmonic tuner is useful, but it is to be adjusted in very tiny amounts in my experience.

Thank you about my m3. It's changed a little. Different moderator, no shroud, just the tensioner. I'm a stickler about it being quiet and at the time this is what it took to make the gun a click noise. It just wasn't balanced to my liking because I do a lot of odd position shooting away from the bench but still on a rest or bag of some type. It's very much personal preference.
 
Tensioning is a double edged sword. Especially with a FX because you aren’t really tensioning a solid piece of steel. And even when you do tension a solid steel barrel, you have to do it properly. Most guys that tension a FX barrel and feel it was successful, might be walking a fine line. I started tensioning Impact barrels back in 2020 and noticed some positives and some negatives as my process evolved. Two standouts were temperature sensitivity and the width of an accuracy node. I finally switched to real barrels on two of my Impacts and the one with a modified FX barrel on it is no longer tensioned.
Very much this it's a tightrope walk. You compress the liner slightly in the barrel tube and then you stretch the barrel tube slightly with the tensioner. For me it was was all about deadening the harmonics of the 700mm as mine was moving like a cracking whip and the precision I had before the tensioner was lost. If you don't run a tungsten hammer and 150 bar+, the tensioner is going to confuse things sooo much more. It took me a year to get the fun back to what I wanted. It was so bad I almost gave up on the tungsten hammer and 34 grain slugs above 900fps. That's another thing I may not have done too. The slug liner took away pellets under 25 grains for my 22.

I spent the money and time, my honest opinion is that the tensioner and tungsten hammer very nearly ruined the enjoyment of the gun. The pellet liner shot <30 grain slugs great and all the pellets with a crazy high shot count. Now my gun shoots great and it's too powerful to use in most settings. It's basically a low power rimfire with really good (comparitively) projectiles. So i bought a dreamline in 25 😂

If you want the looks, the carbon shroud may help that. If you want some tension, put a plastic spacer collar between the shroud and the trigger block that allows you a half turn of interference to tighten against. That method was way better with the stock hammer weight imho. It was also the best precision with the most projectiles I've ever run into for a single tune. I really ruined a good thing. I only relay this to save you the expense and disappointment I felt for a while. Odds are I put my gun back at some point too!
 
Very much this it's a tightrope walk. You compress the liner slightly in the barrel tube and then you stretch the barrel tube slightly with the tensioner. For me it was was all about deadening the harmonics of the 700mm as mine was moving like a cracking whip and the precision I had before the tensioner was lost. If you don't run a tungsten hammer and 150 bar+, the tensioner is going to confuse things sooo much more. It took me a year to get the fun back to what I wanted. It was so bad I almost gave up on the tungsten hammer and 34 grain slugs above 900fps. That's another thing I may not have done too. The slug liner took away pellets under 25 grains for my 22.

I spent the money and time, my honest opinion is that the tensioner and tungsten hammer very nearly ruined the enjoyment of the gun. The pellet liner shot <30 grain slugs great and all the pellets with a crazy high shot count. Now my gun shoots great and it's too powerful to use in most settings. It's basically a low power rimfire with really good (comparitively) projectiles. So i bought a dreamline in 25 😂

If you want the looks, the carbon shroud may help that. If you want some tension, put a plastic spacer collar between the shroud and the trigger block that allows you a half turn of interference to tighten against. That method was way better with the stock hammer weight imho. It was also the best precision with the most projectiles I've ever run into for a single tune. I really ruined a good thing. I only relay this to save you the expense and disappointment I felt for a while. Odds are I put my gun back at some point too!
You’re preaching to the choir. This Impact was three Impacts in the making. Built one, what I learned that was good moved to number two. Once done with number two I knew what I needed for number three. Fortunately FX answered my prayers with the M3 by giving me some base features in that gun that I either added to my MKll’s or wished they had. So the final build became my air powered powder burner. Rarely shoot it. The gun never leaks, has slow shots or any other issues. But it’s wicked. So it must be treated like a .22 rimfire. When the fantasy became reality, it lost its luster. I still bust it out from time to time and push its accuracy and consistency limits. But even picking mice off a feeder at 130 yards at night lost its luster. I was like OK, that’s 10 out of 14, I’m bored. Give me a pellet gun.

IMG_4868.jpeg
 
You’re preaching to the choir. This Impact was three Impacts in the making. Built one, what I learned that was good moved to number two. Once done with number two I knew what I needed for number three. Fortunately FX answered my prayers with the M3 by giving me some base features in that gun that I either added to my MKll’s or wished they had. So the final build became my air powered powder burner. Rarely shoot it. The gun never leaks, has slow shots or any other issues. But it’s wicked. So it must be treated like a .22 rimfire. When the fantasy became reality, it lost its luster. I still bust it out from time to time and push its accuracy and consistency limits. But even picking mice off a feeder at 130 yards at night lost its luster. I was like OK, that’s 10 out of 14, I’m bored. Give me a pellet gun.

View attachment 580271
Impact got built, same as you too powerful but it works.... I'm bored. I've been having fun with a 177 disco on the daily lately because I can just pick off stuff and not worry about 8 grains. 😂

BTW, I know I preach to somebody whose walked the path before I did. I just hope people use the search function or doom scroll past this to absorb the expensive lessons we've learned.
 
Impact got built, same as you too powerful but it works.... I'm bored. I've been having fun with a 177 disco on the daily lately because I can just pick off stuff and not worry about 8 grains. 😂

BTW, I know I preach to somebody whose walked the path before I did. I just hope people use the search function or doom scroll past this to absorb the expensive lessons we've learned.
I think some of us just come full circle. How fast an airgunner can come full circle depends on his ability to reach a certain goal. But I also believe that many, due to never embracing every aspect of airguns just want a dumbed down powder burner. If I still lived in Oklahoma and didn’t live in a neighborhood, three of my more nasty sluggers would be all I’d ever need if I was enamored with airguns. But truth be told, when I lived there, it was the only time in my life that I didn’t even think about my airguns. Too much wind an I was burning powder or slinging arrows.
 
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I think some of us just come full circle. How fast an airgunner can come full circle depends on his ability to reach a certain goal. But I also believe that many, due to never embracing every aspect of airguns just want a dumbed down powder burner. If I still lived in Oklahoma and didn’t live in a neighborhood, three of my more nasty sluggers would be all I’d ever need if I was enamored with airguns. But truth be told, when I lived there, it was the only time in my life that I didn’t even think about my airguns. Too much wind an I was burning powder or slinging arrows.
The dumbed down powder burner and "oh it's not regulated" part of it is what WILL kill it. I like those dudes least. I have a few friends that got into it hearing me talk about it, one i talked into buying a used raw. The other didn't listen and got a 45 cal airforce and has zero iq to throw at it.

I come here and occasionally get to chat with you which is the level of conversation I'm looking for. If there's a higher level forum, please let me know 😂. Until then I'm just here to relay the things I've had to learn so that it can stay alive
 
The dumbed down powder burner and "oh it's not regulated" part of it is what WILL kill it. I like those dudes least. I have a few friends that got into it hearing me talk about it, one i talked into buying a used raw. The other didn't listen and got a 45 cal airforce and has zero iq to throw at it.

I come here and occasionally get to chat with you which is the level of conversation I'm looking for. If there's a higher level forum, please let me know 😂. Until then I'm just here to relay the things I've had to learn so that it can stay alive
Dry lube testing continues. I let the gun sit for long random periods and then shoot a shot or two. Probably will be another month before I can stamp it. But so far so good. Silicone goo could be a problem in some barrels for hunters that don’t treat their guns like an old farm tractor by warming it up. I might start the same experiment with another gun just to see what happens.
 
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The new Donnys are a better design clearly, but comparing apples to apples losing the shroud will always be louder. I will probably have to figure out a way to try a yokozuna at some point.
No shroud takes it from a loud gun(imho) if not running a moderator, to 22 lr LOUD. They need something for sure unless you shoot st a firearms range, then just use an air stripper.
 
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No shroud takes it from a loud gun(imho) if not running a moderator, to 22 lr LOUD. They need something for sure unless you shoot st a firearms range, then just use an air stripper.
Reminds me of the time I accidentally shot my hopped up 25Cal Impact with no shroud while speed testing, just about blew my ears out. :ROFLMAO:
 
Reminds me of the time I accidentally shot my hopped up 25Cal Impact with no shroud while speed testing, just about blew my ears out. :ROFLMAO:
😂 I unscrewed the end cap from my Leshiy and pulled the baffles out. Didn’t replace the end cap. Just left it like a fart can on a 4 cylinder. When I squeezed the trigger my dad and I dropped low to the ground and scurried back in his house. When we got in my mom was standing there wide eyed and asked what blew up.
 
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