Shorten carbon fiber barrel

[26Reload]

Heck...the cutoff barrel looks the same diameter as my Remington mtn rifle noodle barrels.....
Like you said...give it a test...show us it still works good....
Good job...

 

[CBH Australia]

I hope it goes ok.
I thought that they turn a barrel between centres to reduce the diameter only on the section to be wrapped leaving a solid section each end from the original barrel with a shoulder to wrap up too.
Eg they just profile a section in the middle.
When the Smith done my IBI carbon fibre barrel he recrowned it as he wanted to tick all the boxes.
When I collected it he showed where there is a fine black line where he said is C/f and where they Press got the cap on the muzzle end. I said what I just explained. He said I don't know how they are made, I said for all I have read they do turn it down between shoulders. But I can see the line so I hope I don't find a press fit muzzle collar come loose down the track. I haven't shot it enough.

Any good luck with yours and I hope it is as good as a new one and still shoots as it should.

 

[tobnpr]

.580" diameter barrel so I threaded 1/2-28 for 5/8-24 muzzle cap.

80 thou is a bit light for barrel wall thickness, hopefully you won't have any accuracy issues from pressure distortion.

How did you "attach" that bushing you turned to serve as the shoulder to the carbon fiber?

 

[Blancoalex]

tobnpr- once together and get to shoot will be the test if my threading the the muzzle 1/28-28 and making a 1/2-28 to 5/8-24 cap works.
The cap was made from scrap cut off of SS barrel.

I have done similar thing with factory Rem SS barrel with full length epoxied CF tube. It ended up shooting the same ,consistent 3/4 MOA as it did before.

 

[Blancoalex]

Here is some CF info that helped me and be sure to have dust mask for personal breathing protection.

 

[tobnpr]

I'm still trying to figure out exactly what you did.
When I blow up the third pic showing the "cap" as you call it- against the CF, it looks seamless against the minor diameter of the tenon you cut.
Can't be, as it would never slide over the tenon- so what is it I'm looking at??

 

[CBH Australia]

I reckon he cut a tenon then threaded it to 1/2"x28 then made the cap , and adaptor to go from 1/2"x28 to the required 5/8" thread of the brake/suppressor etc. There might be a cap for this, sometimes they are knurled.

I reckon he had a nice tight thread, nipped up the new adaptor to the carbon fibre tenon with everything cut true and square, maybe the slightest concave leade on the back of the adaptor tenon to make it all seem seamless and completed the final machining of the crown after the cap(adaptor) was tightened on. In the images the seam seems seamless but it must be there as it's screwed onto the end of the barrel. Maybe he even had a larger diameter to start and machined that down to meet the C/f wrap after using a pipe wrench to tighten that cap hard. Then just turn down to suit taking the marks out.
Unfortunately that is all above my skill set but I to tinker on an old school lathe.

 

[CBH Australia]

My limited knowledge is you cant do it.The blank is spun down smaller for wrap,sized thicker on ends for brake.That is a terminattion point for wrap to but too.

Essentially that's how abs barrels used to do it back in the old days before proof research bought them.

I hope it goes ok.
I thought that they turn a barrel between centres to reduce the diameter only on the section to be wrapped leaving a solid section each end from the original barrel with a shoulder to wrap up too.
Eg they just profile a section in the middle.
When the Smith done my IBI carbon fibre barrel he recrowned it as he wanted to tick all the boxes.
When I collected it he showed where there is a fine black line where he said is C/f and where they Press got the cap on the muzzle end. I said what I just explained. He said I don't know how they are made, I said for all I have read they do turn it down between shoulders. But I can see the line so I hope I don't find a press fit muzzle collar come loose down the track. I haven't shot it enough.

Any good luck with yours and I hope it is as good as a new one and still shoots as it should.

I'm still trying to figure out exactly what you did.
When I blow up the third pic showing the "cap" as you call it- against the CF, it looks seamless against the minor diameter of the tenon you cut.
Can't be, as it would never slide over the tenon- so what is it I'm looking at??

All that said can anyone see how IBI have done this one? I beginning to think it's a threaded cap not just turned down in the middle as described better by @sp6x6 previously.

I doubt it's a pushed on cap and I can see it better now than when I collected from my gunsmith. I think the thread seems likely and the line is not even as you would expect a thread to be running off centre to the longitude of the barrel.

 

[338 dude]

My limited knowledge is you cant do it.The blank is spun down smaller for wrap,sized thicker on ends for brake.That is a terminattion point for wrap to but too.

I know I have read somewhere that a certain carbon barrel maker actually threads the end of the carbon for a muzzle brake I just can't remember who

 

[CBH Australia]

I know I have read somewhere that a certain carbon barrel maker actually threads the end of the carbon for a muzzle brake I just can't remember who

I know that the retailer in Australia listed IBI Carbon Fibre wrapped barrels with a threaded muzzle option.
They also listed a couple of pre-fit barrels.

IBI are a Canadian manufacturer.

International Barrels – When Winning Matters

internationalbarrels.com

 

[LongBomber]

All that said can anyone see how IBI have done this one? I beginning to think it's a threaded cap not just turned down in the middle as described better by @sp6x6 previously.

I doubt it's a pushed on cap and I can see it better now than when I collected from my gunsmith. I think the thread seems likely and the line is not even as you would expect a thread to be running off centre to the longitude of the barrel.
View attachment 277700

The IBI and several others don't have an end cap like you are thinking. The barrel is turned down only through the section to be wrapped and built back up when the fiber/epoxy is wound back onto the barrel. Then tip of the barrel is not turned down, it is left full diameter and finish turned with the rest of the barrel once the expoxy is cured.
There are a few barrels that run a tensioned carbon or aluminum tube where the tip is reduced diameter and a tube is slid over and a nut is torqued on to tension the barrel.

 

[CBH Australia]

The IBI and several others don't have an end cap like you are thinking. The barrel is turned down only through the section to be wrapped and built back up when the fiber/epoxy is wound back onto the barrel. Then tip of the barrel is not turned down, it is left full diameter and finish turned with the rest of the barrel once the expoxy is cured.
There are a few barrels that run a tensioned carbon or aluminum tube where the tip is reduced diameter and a tube is slid over and a nut is torqued on to tension the barrel.

Thanks. I haven't found any reference for the IBI one when I looked.

That's my original contract understanding of how they are all done, and it makes sense. If they are profiling ba blank they may as well just profile it cutting away a parralell section in the middle with shoulders each end to work to. The Knox form must be solid so why turn off the muzzle end and the cap it. Particularly if they are using the term carbon wrapped. Placing a tube around a barrel should be described as sleeved.

The gunsmith said there is cap pushed on (I questioned that) when he showed me a dark line showing after he machined a new crown.
I will try get a better pic as there is definitely a line of sorts.

 

[Gamesniper19]

My background is in CF barrels. I recommend you don't touch the muzzle end. to shorten.
If you have a 2 1/2 inch breech you might be able to get away with cutting a 1/2 inch but that is it.
Huge safety issue trying to do anything else to a CF barrel - if you end up blowing it up, which could happen, it would be very very bad

 

[Gamesniper19]

Essentially that's how abs barrels used to do it back in the old days before proof research bought them.

Sorry, that is not completely true. Mike (who owned and sold ABS to PROOF) made his barrels similar to the way PROOF does it now - although PROOF has updated the carbon and the resin matrix many times since then the inherent build of the muzzle does not allow for shortening. I highly recommend you dont touch the muzzle of the CF barrel, ever