"UPDATE" FX carbon fiber liner sleeve

What a coincidental topic to post. I should have my CF liner deliver today. .30 cal/700 mm for my Impact MKII. I live in GA, and purchased it through Huma Air.

I don't know about other airgun manufacturers, however one negative thing I can say about FX and their accessory support industry is the level of documentation and instruction is almost garbage tier. Huma is pretty good, bit the rest of it is simply not. There's heavy reliance of Youtubers to make video instructions... but that's one guy's take on the operations.

I've received 1 from Ernest and 1 from 910. Both were low gloss / flat finish and came in clear plastic bags with no FX labeling. 

I have what is supposed to be a genuine FX branded carbon sleeve on preorder at SPAW, we'll see how the finish and inner and outer diameters compare to what I received from Ernest and 910 when it gets here.

I recently received mine from 910. Same low gloss/flat finish. No labels, markings, or instructions.

Also, I noticed SPAW has them listed for $30 whereas 910 lists them at $40.

I was not able to wait for FX so i procured my own, funny thing though, i still have to wait for FX as i still do not have the gun i ordered +5 months ago :-(

I was about to order one from 901 until I found that shipping was $18-nah! Have any of you explored the carbon fiber tubes of various sizes sold on Ebay? Apparently there’s a big business for these in the hobby industry for helicopters and drones.

As long as it’s impressively stiff and the ID is a proper fit to the liner, it has an opportunity to make the barrel more harmonically neutral.

The twill pattern visible on the exterior is mostly cosmetic. The core is usually a pultruded construction which aligns the fibers lengthwise for rigidity.

Are the ones that you dont have to Epoxy by FX available yet and does anyone know of anyone besides utah or PA that you can order them from or is taking preorders? 

The .22 sleeves I received from Ernest and 910 only have 0.007" diametrical clearance between the sleeve ID to the liner OD and probably don't need to be bonded... When you tighten the liner lock and the liner buckles/distorts sightly under compression it will lock itself into the carbon sleeve, there's only 0.0035" radial clearance between them.

That being said, I drilled several small injection holes in the carbon sleeve, then coated the liner OD in 2 part epoxy, slid the sleeve over, and then injected additional epoxy between the sleeve and liner to make the liner and sleeve a solid assembly.

I'm still interested to see if there are any dimensional differences between the Ernest / 910 sleeves and the supposed genuine FX sleeve I have on order at SPAW, but I don't have the one from SPAW yet. I have a hunch they're going to be identical... But I could be wrong.

If anyone receives an FX branded .22 sleeve in the next few days, please measure and post the ID and OD.

Does anyone know of any “special sauce” claims about not needing to bond the sleeves? It seems to me the sleeve would need to have a tight tolerance ID and smooth finish to deliver any appreciable benefit. Neither characteristic is true of the common CF tubes I’ve seen. Quite possible FX is doing something special but the prices being discussed don’t lead me to think so. 

Does anyone know of any “special sauce” claims about not needing to bond the sleeves? It seems to me the sleeve would need to have a tight tolerance ID and smooth finish to deliver any appreciable benefit. Neither characteristic is true of the common CF tubes I’ve seen. Quite possible FX is doing something special but the prices being discussed don’t lead me to think so.

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You can make carbon tubes with tightly controlled ID sizes and ID surface finishes with a male mold tool with a precision ground center mandrel. Then you usually pull tension on the center mandrel during cure to help straightness and minimize any sag.

That being said, all parts involved have manufacturing tolerances and the sleeves have to be sized such that the smallest sleeve ID will slide over the largest liner OD-- so there will always be some clearance.

For maximum stiffness benefit you want to completely fill the gaps between the sleeve ID and the liner OD, and the only way to do that is with some kind of 2 part catalyzed adhesive to serve as a liquid shim between the liner and sleeve. Furthermore, because of the length of the bond joint and the minimal clearance between the two parts, for maximum wetted bond line you really need to drill multiple injection holes along the length of the sleeve, inject additional epoxy, then rotate the sleeve on the liner and repeat the injection and spin process a few times. If you want to get really fancy you could vacuum bag both ends and inject and draw the adhesive in under vacuum.

You also want to use a low CTE, slow curing epoxy that won't exotherm during cure so that the epoxy doesn't get hot and impart a bunch of thermal stresses in the bondline during curing. I used EA9394 with a room temp 70F cure.

Does the sleeve really need to be bonded, or is bonding overkill? I didn't test it both ways, but in my mind you're only going to see the maximum benefit with a slow cured, as close to stress free bond as possible, so that's what I did. Results on target at longer ranges say the bonded carbon sleeve is more accurate than no carbon sleeve and 7 o rings between the liner and barrel shroud.

Be interesting to do an accuracy comparison test between bonded and unbonded carbon sleeves. I bonded my superior heavy liner, but I still have a regular superior liner as well as a spare carbon sleeve... If I get some free time I'll test it at 100y both ways, unbonded and bonded.

Thanks for your detailed reply. It sounds like you and I are substantially of the same mind as to the preferred way to do things, and why I have some skepticism about the efficacy of an unbonded tube with a few thousandths clearance. Placing some load on the barrel to force it into intimate contact with the CF sleeve seems at least intuitively like it would be helpful.

Thanks for your detailed reply. It sounds like you and I are substantially of the same mind as to the preferred way to do things, and why I have some skepticism about the efficacy of an unbonded tube with a few thousandths clearance. Placing some load on the barrel to force it into intimate contact with the CF sleeve seems at least intuitively like it would be helpful.

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I mentioned in another thread on here about the carbon sleeves, there is a very large difference in feel when tightening the muzzle end liner lock with the carbon sleeve compared to just having the o rings between the liner and shroud.



Previously I had 7 o rings between the liner and shroud on my 700mm M3, and if you tightened the liner lock down by finger until it touched the liner and then slightly tightened a bit more with a wrench the liner lock would get progressively tighter but never really felt like it hit a wall and stopped… this feeling is a result of the liner buckling between the o-rings. The more o-rings you add between the liner and shroud, the shorter and stiffer the individual “columns” of unsupported liner, but even with 7 o-rings tightening the liner lock still felt “springy” and it never felt like it hit a wall and got really tight. With the factory 3 o-rings between the liner and shroud, especially on a 700mm barrel, the “springy” feeling when tightening the liner lock is very pronounced.



After bonding the carbon sleeve to the liner, the only unsupported sections of the liner are now only 2 short .125” long sections on both the breech and muzzle ends between where the carbon sleeve ends and the liner locks begin. If you tighten the liner lock by finger until it just contacts the liner and then grab a wrench to tighten it, the liner lock gets really tight and feels like it hits a wall about 1/16 turn after contacting the liner (this is on a 700mm barrel.) The carbon sleeve really stiffens the liner and minimizes the liner buckling and associated “springy feeling” when tightening the liner lock.



And as mentioned, the accuracy difference between 7 o-rings and the carbon sleeve was not substantial, but still very noticeable at 100Y+… enough to be well worth the effort of bonding the carbon sleeve IMO.

The .22 sleeves I received from Ernest and 910 only have 0.007" diametrical clearance between the sleeve ID to the liner OD and probably don't need to be bonded... When you tighten the liner lock and the liner buckles/distorts sightly under compression it will lock itself into the carbon sleeve, there's only 0.0035" radial clearance between them.

That being said, I drilled several small injection holes in the carbon sleeve, then coated the liner OD in 2 part epoxy, slid the sleeve over, and then injected additional epoxy between the sleeve and liner to make the liner and sleeve a solid assembly.

I'm still interested to see if there are any dimensional differences between the Ernest / 910 sleeves and the supposed genuine FX sleeve I have on order at SPAW, but I don't have the one from SPAW yet. I have a hunch they're going to be identical... But I could be wrong.

If anyone receives an FX branded .22 sleeve in the next few days, please measure and post the ID and OD.

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I have a 500 and 700 mm 22cal tubes from ernest. Od is .467-700. .465 for 500. Id is .317 -700. .318 -500

I'd like to get a carbon fiber sleeve for my 700mm .25 cal liner. Who has them in stock?

Has anyone experimented and had success with "tensioning" their barrel? Even with the shroud fully hand tightened (Impact Mk II) the shroud and barrel flexes quite a bit. Or should I consider getting a barrel band?

Fx sleeve didn't fit mk 2 500mm 22 .couldn't get to pass jam nut threads. But one fit my m3 30. The 22 cal looks a lot stronger.