Carbon Fiber tubing for FX Impact liner and shroud mods.

Why do you need it?

Mine should be here today. I’ve been waiting for two weeks for 3mm carbon from China. I ordered some carbon fiber from Southern California for now but I had to get 1mm wall thickness, so I bought 14mm ID x 16mm OD and also 16mm ID x 18mm OD and epoxied them together. It’s all I could find that would get here fast. Not really what I wanted to do but did it while waiting for the 3mm walled carbon fiber from China. I’ve been waiting two weeks but it says it should be here today...we’ll see. It definitely tensions the barrel but I didn’t do any accuracy testing with it. My gun is dialed and I’m not messing with it until the 3mm gets here. I’m just going to wait for the 3mm tubing. I tried a different method to stiffen the barrel and reduce harmonics a while back when MtnGhost did his Veteran but mine wasn’t well thought out and didn’t work. That was dampening vibration, this is actually tensioning the barrel. 

Stoti

All the cf you see on ebay doesn’t have the right fit— to big or to small. So i had custom made molds for .22.25&.30 yes custom made 3k carbon fiber liner sleeves. No more oring to mess with and makes the liner more stiffer. 




will be offering then in about 2 weeks 

Ernest 

....so I bought 14mm ID x 16mm OD and also 16mm ID x 18mm OD and epoxied them together.....

Stoti

Click to expand...

My understanding is that the STX and the Superior liners are both 8mm OD. Is that 8mm for .22 and .25 also? So getting an 8mm ID carbon fiber tube would be the first layer? Or I missed something since you mentioned 14mmx16mm thickness tubes. I almost bought a 16mm-20mm tube, but I realized that that 16mm is the barrel OD, and not the liner. 

With the liners i think needs some opening up to fit like Ernest said above.

I just ordered some 3mm wall to put over the barrel house. 20x14x500mm off aliexpress. I might modify my shroud so the CF will slide under. And since it will *hopefully slide on and off would work for all 3 calibers.

Edit, i bought a 8mm ID tube a few months ago and wasn't even close to fitting. Also was drilled way off center lol. At least got a full refund. So Ernest offering ones known to fit is great i think.

Thank you, Glem.Chally. Can someone tell me how the carbon fiber that slips over the liner is secured to the receiver? I assume it has to fit perfectly snug so it cannot allow the barrel to flex since that barrel is still free-floating... Is there some kind of a metal sleeve over the end of the tube where they meet up so the carbon fiber won't crumble with time and stress?

The ID is 14mm, and the OD is 20mm. The carbon tube I ordered came from China and fit perfect. It took 2.5 weeks to get here but fit just right. You still need to use the inner liner(14mm OD) so you have the threaded end piece to attach the moderator and tension the carbon fiber tube. I hate to break it to you guys, I tested mine yesterday and the results were inconclusive because of wind. I went back out this evening and tried again. I started with the moderator cranked down as tight as it would go...At the advice of Newman at FX. I shot a five shot group, loosened the moderator about 1/4 turn and shot another 5 shot group. I kept going until the moderator was loose. I tried it with both the Sumo and 0dB moderators since I had them both handy. The POI shifted around quite a bit and the accuracy did not improve over the standard FX shroud at any of the tensions I tried. I’m not giving up yet but I have a pretty good idea this modification will work better on the .30 and .35 or maybe a .25 if you’re shooting up around 80FPE or more. The accuracy wasn’t bad, it just didn’t really improve anything. And, because I wasn’t using the shroud anymore, it was quite a bit louder than normal. If you like using big heavy moderators, this mod will certainly keep the barrel from drooping. I’ll let you know if I find out anymore when I test it again. I always tell people to test things themselves so they know for sure if whatever it is they’re testing will benefit them, in my case, this doesn’t look like it’s going to help my accuracy much. Don’t want to be a bummer, just sharing my results.

Stoti

 

Thank you Stoti for the details of the setup. So the verdict is still out...

Nice rigs by the way!!!

I ordered some ID 8m OD 10mm x 1meter carbon fiber tube off ebay from someone in S. California. My .22 x 600mm barrel outer diameter was about 8.13mm (can't remember exactly) so had to take some material off. Chucked in my lathe at first but was not enough support so made a jig to clamp in place on work bench. Took off enough material so it was just about an interference fir. Was a really tight fit slipping it over the barrel liner. Did not use any epoxy just some alcohol for lubrication.

Can't say how much it improved the accuracy but it sounds quieter.

Thank you, Glem.Chally. Can someone tell me how the carbon fiber that slips over the liner is secured to the receiver? I assume it has to fit perfectly snug so it cannot allow the barrel to flex since that barrel is still free-floating... Is there some kind of a metal sleeve over the end of the tube where they meet up so the carbon fiber won't crumble with time and stress?

Click to expand...

The fx liners are not an exact size, normally a little over, so the equivalent carbon won’t fit but it is an easy fix. 
I cut a 2” long slit in a length of 4mm carbon rod. with a strip of emery paper in the slit I was able to make a “flap wheel” that fitted into a cordless drill to open out the carbon tube. It is a bit dusty, dirty and does take a few minutes but it is possible to get a very nice fit over the liner.

Ising the same method it is possible to laminate up numerous layers off carbon tube to achieve your desired O/D

Here is an example of a FX liner I fitted to my RAW




Bb

May be off topic here but I have made a custom barrel built for my FX ELITE using STX liners and stainless steel tube 14X2 mm. I didn't use o-rings for the liners but custom made derlin spacers. They work fine for me. 

Here are some photos of the .25 700 mm barrel







And the gun



Installed is the .25 700 mm STX SUPERIOR HEAVY LINER barrel and from top to bottom:

.22 600 mm STX SLUG A barrel

.25 600 mm ST barrel

.22 500 mm ST barrel

The 700 mm barrel flexes a lot when shooting but accuracy (for me) is very good.

This is a 7 shot group at 75 m with JSB HEAVY MKII at 840 fps the first day of testing



and two more 5 shot at the same distance the same day





seems there only 3 shots but actually there are five!

All the cf you see on ebay doesn’t have the right fit— to big or to small. So i had custom made molds for .22.25&.30 yes custom made 3k carbon fiber liner sleeves. No more oring to mess with and makes the liner more stiffer. 

will be offering then in about 2 weeks 

Ernest

Click to expand...

cant wait!!! Even though my impact is shooting really awesome but definitely will order from the grand master!

Yeah, my gun is very accurate too. I was hoping to squeeze a little more accuracy out of her by stiffening the barrel with tension and hopefully reducing vibration. That was asking a lot though...My gun is capable of 1/2” @50yds and 1”-1.25”@100yds very regularly. I’m talking five shot groups over and over again, not just occasionally or three shot groups, or cherry picking the best groups. Not trying to brag, just give you an idea of my gun’s capability and what I was trying to improve upon. It was asking a lot. The results didn’t show me any improvement in accuracy but like I said, this might work great for more powerful .25(80-110FPE), .30 or .35 cal. I really wanted it to work, especially since it was my 3rd attempt at different ideas and because I spent some money on the carbon tube. Just to specify one more time...The interior shroud is 14mm. I bought 14mm ID x 20mm OD and it slipper over the inner shroud perfectly. No sanding, buffing, lubing or anything necessary. It was a perfect fit. Some have emailed and messaged me about running the carbon fiber tube under the large external shroud. It can be done but you would have to modify the shroud quite a bit. Good luck if you proceed! 
Stoti

I wouldn't mess with the shroud. But as Ernest said, a small spacer at the back of the shroud to tighten against will tension the barrel also.

I'll play devil's advocate here, and disclose that I am not a fan of barrel liner systems. Seems to me, folks are going to considerable time and expense to duplicate the physical properties of a solid barrel. If I were interested in competitive shooting with an FX rifle, I believe I would have a traditional solid barrel of my choice fit to the rifle. Just my opinion, and my wife says I'm always wrong. That said, it would be an interesting exercise, and I guess that's what hobbies are all about.

FX liners can be extremely accurate. That’s why many people use them in their builds with other brands of guns. I just wanted to try and squeeze those 1” groups down to 5/8” and make it less hold sensitive. Tensioned barrels, free floated barrels, hybrid barrels, who knows if one is actually better than another. There are proponents of each and plenty who don’t like each. I like to experiment and tinker, in this case it just didn’t improve my accuracy. Have a good one. Stoti

Has anyone had positive results from these mods to report?

Stoti, Unless I missed it,, Being dyslexic, your skipped the fundamental beginning of the foundation if you will. First you have to put a cf tube over the liner it's self. It is the foundation of the entire exercise. And yes, 8mm id is correct. 

I have been building these for a few years now as has Hobbyman2007. We have had extremely good results. How bout under .20" at my home 80 range . Large groups are still around 3/8". Rarely less. 

We have been using both FX Liners and Redman Liners from Brownell's Gunsmithing Supplies. All are accurate. 

Remember, the cf is not only to help harmonics. its primary purpose is to stiffen the entire bbl. system to prevent day to day poi shifts. Particularly when used for something other than bench shooting. Makes for much more reliability in the woods.

Many of my bbl. are multi wrapped to the point that they are now ultra light bull barrels.

Knife