Carbon fiber pump tube

[SawneyBean]

Has anyone ever tried to make one?   It just seems like such an easy and obvious way to cut weight that I'm guessing there's some reason why it's not being done.   

Maybe the interior diameter isn't uniform enough?

[TerryM]

  Might not hold up to continual wear.  Just a guess.  Carbon fibers laminated with some kind of stickum.. epoxy?

  A gun can be to light.  Of course, I am biased, I like wood and steel best.  And hold the camouflage.

[SawneyBean]

What I'm envisioning here is a backpacking rifle, so I want to make it as compact and lightweight as possible without sacrificing power.   I'm starting with a Crosman 362 and I'm going to start by replacing the rear stock and breech.   I've already got a steel breech and pistol grip from a 1322 and I'm either going to add a takedown stock or a folder.  Ultimately I want to build it up to about a 20 ft lb rifle.

It just seems to me that a new pump tube would be an easy place to cut weight and I suppose aluminum could be used even more easily than carbon.

[Rob M]

the interior of the tube isnt smooth enough , if it was and was very thick wall , I guess it could be done. It would need have several epoxy layers to even have the strength to hold a seal , nevermind the porosity

[Spacebus]

the interior of the tube isnt smooth enough , if it was and was very thick wall , I guess it could be done. It would need have several epoxy layers to even have the strength to hold a seal , nevermind the porosity

What if an aluminum liner were used?

[Rob M]

that would work , look at how thin walled an 880 tube is

[Samcirrus]

Carbon fiber can NOT handle the heat that is created by pumping high pressure air! The resin will crumble and weaken. That's why pump tubes have to be steel.
Low psi probably fine, anything over 300 psi, no way.

[dan_house]

pump tube? like a 1377 kinda thing?

two words: structural integrity ......  having the pump arm slot and the holes for screws would serisouly weaken the tube. Alos agreee that you would need a very thin steel or aluminum liner for the piston to run in, as Rob is correct the inside of the tube is not all that clean (at least the CF Ive been working with lately)

maybe for a 2240, where those holes and slots are a lot smaller

[SawneyBean]

I'm not sure that CF couldn't handle the heat.   It's being used on firearm barrels these days.

I'm thinking that aluminum is definitely the way to go however. 

This is kind of a long term build plan.   First off I'm just building a tinker toy rifle.  I've ordered a flat top piston and valve and will replace the transfer port and breech and swap the rear stock out for a pistol grip and folder.    That should result in a pretty decent backpacking rifle that can take small game out to 35 yards. I've already swapped fhe rear stock for a pistol grip and modified the forearm to fully close and I'm waiting on parts to go further with the build. 

Aesthetically, I love the way it looks so far, except for the brown slabs on the pistol grip and the slight gap in front of the trigger guard. 

Making a new pump tube might come after that.   If I can get aluminum tubing with the correct dimensions then it ought to be an easy job.   I've done full length pcp conversions on 22xx and qb rifles in the past, so I don't think milling an aluminum tube will be much of a challenge.

I've got a few crazier ideas that I might want to pursue after that as well, but the build process here is going to be most of the fun. 

[Madd Hatter]

  Might not hold up to continual wear.  Just a guess.  Carbon fibers laminated with some kind of stickum.. epoxy?

  A gun can be to light.  Of course, I am biased, I like wood and steel best.  And hold the camouflage.

Cost and the wear problem. Now if someone wrapped an very thin steel tube you could get by with it but it would be too expensive for most to be willing to spend on a pumper.

[2K1TJ]

I would try aluminum, with a thicker OD than the factory one. It wont be ridid enough using factory thickness. You'd also need a poly hammer to keep from galling the aluminum, and save a little more weight. I would do the math first to see how much weight you'd save. It may not be worth the trouble.

Another thought is using a straw barrel and sleeving it with a carbon fiber tube.

[rsterne]

The slot is a weak spot in CF or aluminum.... steel preferred, IMO....

Bob