Carbon fiber barrel tensioner on Fx impact only

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whitetail17

Member
Oct 16, 2017
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pa, United States
How many on here have either used the around 13mm-14mm carbon fiber spacer between the factory shroud and gun or removed the shroud entirely and replaced with longer carbon fiber tube? Both scenarios provide a way stiffer barrel system even if your already have the carbon fiber liner installed for the barrel liner.

My M3 .30 sniper shoots very well with just the carbon sleeve over the superior heavy liner, but wondering if could experience even tighter groups at any distance utilizing one of the two barrel tensioning systems above.

My plan is try the harmonic balancer with complete shroud whenever they become available in 700mm. If I'm doing that, should i wait to install the tension and do it all together so I will have some type of harmonic adjustability after tension is applied?
 
I’ve got the liner sleeve and the 16x20mm exterior CF tube tensioned with the harmonic tuner. I’m still tuning but it’s a nice stiff unit topped off with the Donny FL moderator. Where I shoot I often have light to 10 mph swirling winds making it difficult to know when I have a good tune. So I keep doing it again and again, eventually I’ll find it.
 
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I have a spacer I made out of Delrin and it really tightens things up. I will be tensioning with a full carbon shroud when my tubes get here.

Haven't done much shooting with my .30 Sniper yet but it tuned right up and shot <MOA @ 100 yards with the JSB44.75 pellets first time out with the carbon sleeve and Delrin spacer.

Have not spent much time with e the Harmonic Tuner yet so I really can't say much about it. I will get to it soon enough though.
 
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I have a spacer I made out of Delrin and it really tightens things up. I will be tensioning with a full carbon shroud when my tubes get here.

Haven't done much shooting with my .30 Sniper yet but it tuned right up and shot <MOA @ 100 yards with the JSB44.75 pellets first time out with the carbon sleeve and Delrin spacer.

Have not spent much time with e the Harmonic Tuner yet so I really can't say much about it. I will get to it soon enough though.
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I made my initial spacer out of Delrin also. I found it to be temperature sensitive. The torque value on my shroud changed with the air temperature. CF is much more stable. You should switch. Just trying to save you some lead.
 
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Consider the structure of the impact before u go tensioning that barrel.

the structural connection between the trigger action and valve block is a 1/4 alum plate running on top of the gun. 
If the barrel gets tensioned, it’s not pulling straight out of the action like most conventional actions.

the stress or force to that plate want to bend it down. 
granted ur not tensioning enough to damage anything, but I’m guessing it’s enough to make it more hold sensitive. 


 
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I have a spacer I made out of Delrin and it really tightens things up. I will be tensioning with a full carbon shroud when my tubes get here.

Haven't done much shooting with my .30 Sniper yet but it tuned right up and shot <MOA @ 100 yards with the JSB44.75 pellets first time out with the carbon sleeve and Delrin spacer.

Have not spent much time with e the Harmonic Tuner yet so I really can't say much about it. I will get to it soon enough though.
Click to expand...

I made my initial spacer out of Delrin also. I found it to be temperature sensitive. The torque value on my shroud changed with the air temperature. CF is much more stable. You should switch. Just trying to save you some lead.
Click to expand...

This is only temporary as I have CF tube on it's way on the slow boat. Also, I shot <MOA groups at 100 yards with the Delrin my fist time out with the .30 M3 so it werqs fine. Yes, the CF is better but it's not here the Delrin is so I suffer with it in the first world for now. Poor Poor me. ;^)
 
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Consider the structure of the impact before u go tensioning that barrel.

the structural connection between the trigger action and valve block is a 1/4 alum plate running on top of the gun. 
If the barrel gets tensioned, it’s not pulling straight out of the action like most conventional actions.

the stress or force to that plate want to bend it down. 
granted ur not tensioning enough to damage anything, but I’m guessing it’s enough to make it more hold sensitive. 

Click to expand...

Tensioning the barrels werqs well I have thousands of rounds through my Gen1 with the barrel tensioned. It shot lights out before tensioning and it shoots lights out after like on a good day mostly <MOA and often as not .5MOA inch groups at 100 yards in .25 caliber and I did not noticed any more hold sensitivity. 
 
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My thoughts, please correct me if I am thinking this wrong. At the point were the barrel exits the gun, it is not 100% tight. It feels like that area before it gets to the breech with locking screw, the barrel in the gun is supported slightly by 0 rings. So if the barrel gets handled or bumped (even though it is not near a stiff than when tensioned) it always returns to the same place. 

With either of the two tensioning methods, there will be friction right at end of gun between the gun itself and whatever you used to apply the tension while screwing on the moderator. The complete carbon tube or just a spacer with original shroud.

Now when the barrel gets bumped and moves at that point, It will never return to the same place. It may group good, but poi may change if gun is handled or bumped.

THIS IS THE EXACT RESEASON my delta wolf did not shoot well. The barrel always had inference at that part of gun due to the electrical connection and o rings.

Thoughts ....
 
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I replaced all the orings that "connects/holds" the barrel floating to Buna90, also I am in Canada/Toronto. My Temp swing is definitely not so aggressive as in the Southern States. Right now the outside Temp is sub zero in C and these orings feels like a plastic not a rubber.

The other thing I need to mention is that I got the barrel tuner = shroud, and it is CF. For now behaves well and I will not add a bushing in front of front-block. Also no LDC/moderator weight up front to pull the barrel down as - you would be hanging a pickuptruck there
 
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My thoughts, please correct me if I am thinking this wrong. At the point were the barrel exits the gun, it is not 100% tight. It feels like that area before it gets to the breech with locking screw, the barrel in the gun is supported slightly by 0 rings. So if the barrel gets handled or bumped (even though it is not near a stiff than when tensioned) it always returns to the same place. 

With either of the two tensioning methods, there will be friction right at end of gun between the gun itself and whatever you used to apply the tension while screwing on the moderator. The complete carbon tube or just a spacer with original shroud.

Now when the barrel gets bumped and moves at that point, It will never return to the same place. It may group good, but poi may change if gun is handled or bumped.

THIS IS THE EXACT RESEASON my delta wolf did not shoot well. The barrel always had inference at that part of gun due to the electrical connection and o rings.

Thoughts ....
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Nice observation. 

I did try replacing the B12 and B13 orings on my M3 with NBR90. The smaller B13 NBR90 orings got totally shredded when attempting the barrel install. You could tell there was going to be trouble right away. I suspect this may have to do with the tighter tolerances on the M3. B12 oring worked out OK in NBR90. Can't say if this helped, though as I didn't really have any POI shifting issues before, but thought I'd try it since I had the gun apart.

Impact barrel mounting system seems like something that shouldn't work but it does, and that's what counts to me. 
 
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So, you toke your gun apart...and now shredding the orings when removing the barrel.

Are you sure that you have a right procedure to put the FX together?

Because it is not just like assembling the parts and screws and done, but there is a sequence what to do and how to do and no shortcuts....the barrel with all those orings need to slide in smooth.
 
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Click to expand...
Click to expand...

So, you toke your gun apart...and now shredding the orings when removing the barrel.

Are you sure that you have a right procedure to put the FX together?

Because it is not just like assembling the parts and screws and done, but there is a sequence what to do and how to do and no shortcuts....the barrel with all those orings need to slide in smooth.
Click to expand...

The issue was only when attempting to use harder NBR90 orings instead of factory spec. I've had the barrel in and out many times with the OEM NBR70 14x1.5mm orings (part B13 in the diagram). It is a tight fit, but the barrel slides in smoothly and without damage to orings, so I know how it should feel and how to install it. With the NBR90 versions of those orings installed, the barrel just doesn't want to go in no matter how you finesse it. I was at the point where I was pretty sure it wasn't going to work and it was requiring an unacceptable level of linear force, so I tried twisting the barrel. That is probably what did the (harder, non-standard) o-rings in.

I suspect this is down to tighter tolerances of the M3 and the 1.5mm orings not having enough thickness to comrpess in NBR90. The 13.95x2.62mm (size #113) oring at the front worked out in NBR90, and that may be due to being thicker and still being able to compress enough to allow smooth barrel install.
 
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Mine is a MK2 and was thinking if I made peek spacers turned down on each end out of one rod to slide into where the orings go then cut it in the middle u could pull the barrel install the spacers facing each other and slide the barrel threw the assembly so they can't fall out they will keep each other in place don't know if it will work just a thought of how to stiffen up the mounting of the barrel to the frame then I would not use the spacer to tension the barrel set up 
 
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