FX liner with Carbon Fibre “wrap”

Doesn’t Proof Research do this with Firearm barrels already? In fact, Claudio Flores told me at RMAC that he has one on his .30 AAA EVOL.

https://proofresearch.com/barrels/

I think it’s a great idea. Keep us posted. If you want to see just how much the FX STX 700 mm barrels flex look at the video on Facebook of M. Dubber shooting the Gunslynger event at PAC with his (loaned) Impact pumper. That’s some serious flex on every shot. Anything you can do to make those barrels stiffer is great. 

Mike

I have done it already as I think someone else also has, I have a 600mm slug liner and two 700mm on the way but with collet system instead of the bonding done with the 600mm.

Makes sense to me to epoxy a carbon fiber tube over the FX barrels. IMO, these barrels are pretty thin and subject to bowing and vibration. I believe the accuracy and consistency would improve dramatically.

Makes sense to me to epoxy a carbon fiber tube over the FX barrels. IMO, these barrels are pretty thin and subject to bowing and vibration. I believe the accuracy and consistency would improve dramatically.

Click to expand...

Yes we did just that with the 600mm, plus we used the inner carbon tube to tension the FX Liner inside of the shroud, instead of compressing it as in the FX system.

Any updates on the CF sleeving?

If you had a larger diameter sleeve and the liner was perfectly centered, you could possibly use something like spray foam instead of epoxy.

I have seen Ernest Rowe put the carbon fiber sleeve on Fx barrials and I was wondering does anyone have sizes of the .25 cal and 30cal and 35 cal I want to do it to all my barrials is there a place to buy them thank you. 

Has anyone done this for the Crown Continuum ultralight barrels? I was thinking about sleaving my liners in carbon, and having new guides 3D printed to fit and properly center the liner in the barrel. Has anyone had success with finding carbon for .25 or sizes other than .22, and if so, where did you find them?

Pat

Firstly, I find this all very fascinating how people are going about to stiffen barrels and hopefully null the effects of harmonics. I machined up a harmonic balancer for my 22lr and the result is amazing, being group sizes at 50 metres achieved with cheap standard velocity ammo that took me prime match ammo to achieve pre balancer.

I’m not a material scientist, metallurgist or even a professional engineer. But I’m am an aircraft mechanic who has seen 1st hand when bonded dissimilar materials seperate over time due to temperature changes from both extremes. The reason is because of the coefficient of linear expansion. In simple terms, different materials grow/ shrink at different rates with temperature change. Bond them together and they will fight each other. If you have an analog temp gauge on your bbq, chances are it works with a coil of a bimetallic strip. ( 2 metals). When the temp goes up, they expand at differing rates and that’s what spins the needle around.

So, steel expands at roughly 3 times the rate of carbon FRP. After you bond the barrel liner to the carbon tube, would these stresses be induced by temperature change? Could a rifle sighted in on a cold morning progressively change its point of impact as the day drags on and the hot sun warms up the barrel? Would it be better to coat one of the mating surfaces with a release agent so they never really stick and that way it is still a nice snug harmonic killing fit that is free to expand / shrink as temp changes?

Just a theory, and it could be full of crap......

I am a mechanical designer lot of FEA and also I have been exposed to CF tubes (archery competition shooter for over a decade) and lot of design involving bonding and epoxy's.

I don't want to detail each step pros and cons just saying I did not do it.

Roughly, the CF tubes are made on mandrel and ground the outer cylinder (don't even think you would wrap it yourself) and the wall thicknesses is not consistent along the length. I am talking arrow tubes that cost 500 to 700 bucks a dozen (Easton and Carbon Express, high end competition arrows), all those have stiffer and weaker side spines and not continuous along the entire length. Then you want to bond the CF tube to the sleeve with an epoxy? I worked with many high end manufacturers and very expensive epoxy's, you do not expect the epoxy will evenly fill the gap and the liner to remain concentric along the mechanical centerline...also to go further how it cures will push the materials around depend of the epoxy layer thickness all different. You may end up with "good enough" straightness but most likely not.

Now to get to harmonics, the CF will fight the inner liner vibration frequencies, but the spine have weaker and stiffer side or multiple weaker and stiffer sides....you brake the natural oscillation of the inner liner and amplify the side effects from the CF sleeve...I tried in fewer words possible but hoping you got a picture.

If the CF sleeve would make any good to the barrel - or to a scoring card most importantly overall - don't you think FX would make it that way at fabrication level?

Has anyone played around with adding a couple of extra o rings at shorter intervals and seen what effect that has? I’m a big fan of the KISS principle, and two extra o rings are cheaper than carbon reinforced plastic sleeves.