Author Topic: Full Length Carbon Fiber Barrel Sleave? (Read 8413 times))

FuzzyGrub · « **on:** July 25, 2014, 11:13:52 AM »

I am considering building up another Mrod. I am thinking about using the 25 cal breech but with a fully CF lined 177 or 22 barrel. The CF will need be removed from TP and all set-screw locations, and would use 25 cal shroud spacers. The breech would need the corresponding bolt and small spacer to fit the smaller mags.

I am most concerned about how the CF will hold up sandwiched between barrel and breech. Expansion and contraction of different materials? In general, do you think it is worth doing? Or just another stupid fuzzygrub idea?

Thanks, I'd appreciate your feedback.

ezman604 · « **Reply #1 on:** July 25, 2014, 11:21:50 AM »

Here's the CF shroud I added to the KillerBRod Gene built.
http://www.gatewaytoairguns.org/GTA/index.php?topic=62950.msg661187#msg661187

FuzzyGrub · « **Reply #2 on:** July 25, 2014, 11:53:58 AM »

A very sharp looking gun!

I see the custom CF shroud but didn't see anything about sleaving the barrel and specificly the part that will go in the breech. Most pics had a shroud on it, so couldn't tell.

Bwalton · « **Reply #3 on:** July 25, 2014, 12:06:26 PM »

Quote from: ezman604 on July 25, 2014, 11:21:50 AM

Here's the CF shroud I added to the KillerBRod Gene built.
http://www.gatewaytoairguns.org/GTA/index.php?topic=62950.msg661187#msg661187

where can i get some of that CF?

ezman604 · « **Reply #4 on:** July 25, 2014, 12:19:00 PM »

Got mine on eBay. From China.
I cut a Delrin bushing for the breech end to support the shroud. Also a Delrin bushing center support and one for the crown end. VERY snug fit, pressed on.

rsterne · « **Reply #5 on:** July 25, 2014, 12:23:16 PM »

I used a CF barrel sleeve on my .224 cal Hayabusa....

However, it is critical that the setscrews go THROUGH the carbon fibre and bite into the steel or this can happen....

I didn't get a Chrony reading on the barrel, but it did travel the length of my shop (20') and hit the target backstop on the very first shot.... After the mods below I had no more problems....

My CF sleeve is a 1/16" wall, increasing the OD of the barrel from 1/2" to 5/8" and it makes a HUGE difference in stiffness.... Sean has a 1/2" OD .357 cal liner that he has sleeved with a 1/8" wall CF sleeve (3/4" OD).... It is wayyyyyyyyyy stiffer than a similar sized steel barrel at a fraction of the weight.... I would not hesitate to epoxy a CF sleeve to any relatively slim barrel to stiffen it.... Most of the fibres should run lengthwise for best results, the twill layer on the outside is just for show....

Bob

Motorhead · « **Reply #6 on:** July 25, 2014, 12:29:43 PM »

Had also done it on a LW barrel used on the .177 M-rod.
Used the Ebay from China tubing as well

rsterne · « **Reply #7 on:** July 25, 2014, 12:34:27 PM »

Guys, the OP is talking about a sleeve to stiffen the barrel, NOT a shroud, unless I read it totally wrong....

Bob

Bwalton · « **Reply #8 on:** July 25, 2014, 12:38:16 PM »

Quote from: ezman604 on July 25, 2014, 12:19:00 PM

Got mine on eBay. From China.
I cut a Delrin bushing for the breech end to support the shroud. Also a Delrin bushing center support and one for the crown end. VERY snug fit, pressed on.

I will try to find it unless you have a link to it?

Motorhead · « **Reply #9 on:** July 25, 2014, 12:44:23 PM »

Quote from: rsterne on July 25, 2014, 12:34:27 PM

Guys, the OP is talking about a sleeve to stiffen the barrel, NOT a shroud, unless I read it totally wrong....

Bob

Thats what I am showing BTW

... 16mm (.630") I.D. X 18mm O.D. STIFFENING tube over the barrel.

ezman604 · « **Reply #10 on:** July 25, 2014, 12:54:05 PM »

A full shroud with three support bushing WILL stiffen whatever it slides over.

Rdsail · « **Reply #11 on:** July 25, 2014, 02:11:11 PM »

here is mine on my bottle disco.

The the carbon shroud.

rsterne · « **Reply #12 on:** July 25, 2014, 02:17:06 PM »

Absolutely true, DEz, I was just trying to make the distinction for those who thought they were the same thing.... Doing BOTH like rdsail has done is even better, although a support mid-way would help....

Bob

Rdsail · « **Reply #13 on:** July 25, 2014, 03:26:41 PM »

I agree with bob. I ended up sleeving the barrel for accuracy. I bought a TJ barrel and harmonics were messing up the accuracy. The first thing I did was to put the carbon shroud. That made little to no improvement. Then I proceeded to add the barrel sleeve. That made a huge improvement and set the accuracy where I wanted it. Both things together make the barrel very stiff. There is very little movement if you push the the muzzle in any direction.

Forgot to mention. I left about 1.5 inch with out the carbon sleeve at the muzzle end. That is to add weights if needs. You can see it in the picture. currently I'm not using any weights.

RayK · « **Reply #14 on:** July 25, 2014, 03:42:08 PM »

Quote from: Rdsail on July 25, 2014, 03:26:41 PM

I ended up sleeving the barrel for accuracy. I bought a TJ barrel and harmonics were messing up the accuracy.... add the barrel sleeve ... made a huge improvement and set the accuracy where I wanted it.

Hi Rdsail.

That is good to hear and I enjoy reading about your cool and effective airgun mods.

I believe Fuzzy was asking about extending the CF all the way inside the breech or if it is enough to go up to meet the breech and I'm interested in that too.

Did you stop at the breech or did you have the CF extend all the way like RSterne did?

Ray

FuzzyGrub · « **Reply #15 on:** July 25, 2014, 03:44:24 PM »

Thanks for the reply guys. Most of the barrel sleaves I have seen stopped at the breech. Bob's pictures are close to what I want to do. Only a very small part of the barrel will not be covered, where the 177/22 mag engages.

The goal would be to stiffen the crosman 177 or 22 barrel, and the OD be equal to 1/2" so it would fit the the 25 cal breech. All set-screws would contact barrel, not the CF.

Rdsail · « **Reply #16 on:** July 25, 2014, 03:49:38 PM »

I stopped at the breech. my barrel is ½ think. and the the barrel goes full width into the breech for about 2 inches. the it steps down in Diameter to fit the original barrel width.

Bob might current me on this. My only concern in running the Carbon sleeve into the breech is the set screws. Carbon fiber is very strong but it is it can delaminate some if you put pressure like of a set screw or the set skew will start drilling into it. I rather have have metal to metal contact in barrel and breech. A way around this can be to drill the Carbon so the set screw goes all the way to the metal. this would also help to index the barrel.

Edit: FuzzyGrubb. you cleared my concern before I summated my post.

Motorhead · « **Reply #17 on:** July 25, 2014, 03:56:59 PM »

Full length ... done that too

Made up a Full CF sleeved BRASS .20 cal Sheridan barrel for a buddies FWB P70

CF went from the muzzle all the way to breech, then area where it slipped into Receiver was an epoxied on aluminum sleeve for grub screws to anchor onto.

Stiffened up the THIN brass barrel a bunch !!

** Only picture is this one which was a second one I did for my M-rod done in a similar fashion.

Jr_Explorer · « **Reply #18 on:** July 26, 2014, 12:18:46 AM »

So are these carbon fiber tubes close enough to a press fit so that you just tap in onto the barrel or are you trying to epoxy it to bond the two together?

rsterne · « **Reply #19 on:** July 26, 2014, 01:52:39 AM »

You want a slide fit and then epoxy it on ....

Bob

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Full Length Carbon Fiber Barrel Sleave?

Author Topic: Full Length Carbon Fiber Barrel Sleave? (Read 8413 times))