..

Didn't Winchester do this to a light weight version of the Model 50...maybe is was 59?

I don't understand, it is easy but you don't know how to do it. If you have ever shot one you would understand why you do not see more of them. You need to add weight inorder for them to balance and hold point of aim.
Do you have access to an autoclave to cook it when done?
Butch

Occasionally carbon wrapped barreled guns of a particular manufacturer make their way to my shop with accuracy complaints. The majority of these have loose bores. In order to reduce the weight on these otherwise varmint weight barrels, they are turned down considerably and then wrapped. Turning them down to this degree can't help but release stresses causing the problems that I've seen. Sometimes a quick look down the bore is all it takes to raise concerns. Based on what I've seen, this particular company needs to start checking these barrels from end to end before they leave the shop.

Having been involved with Composites for more years than I care to admit to , I see NO REAL advantage

in Carbon Fiber wrapped barrels . The Shop I used to work for and still have affiliation with

has one of the largest Autoclaves in the World , Pultrusion winders , vacuuming , RTI pressing Etc. .



Now if I saw an advantage I would do one for myself . Retains the heat in the bore longer which I

believe is counter productive . Sure it stiffens the bore so does Fluting which IMO is a far better

way to fly .

Isn't this what Christensen Arms does?

How do you figure fluting stiffens the bore?
Butch

Doc -

Perhaps I have misunderstood the hype which was built for promoting carbon-fibre wrapped barrels, but I don't think they were constructed mainly for their stiffness OR cooling.

I thought they were conceived mainly as an over-reach of the ultra-ultra-light arms fad.

There comes a point when trying to make rifles lighter and lighter, where it is unsafe to reduce the diameter of the barrel any more if the barrel is made only of steel.

Some bright dude(s) though decided they COULD make barrels even lighter [and therefore lighter rifles], if they reduced the amount of barrel steel even further, and wrapped what they end up with in carbon fibre. Supposedly, that fibre would lend enough strength to the assembly that the barrels would still be safe to shoot, without weighing as much as if they were all steel.

Of course, as has been correctly pointed out by you and others, going to that extreme has other costs to offset the supposed benefits of the lightness gained. Yet another of those costs is, they cause more recoil with a given cartridge and load because of their lighter weight.

To me the whole concept is just another example in this world of how a basically useful idea (a lighter rifle for hunting in the mountains) can be taken to a counter-productive extreme.

Me, I still believe in what Townie W said...if a shooter can't easily carry and use a rifle that weighs 5% of what the shooter weighs, where and when he needs his rifle, the shooter either needs an exercize program or needs to re-evaluate what portion of shooting is a feasible sport for him.

quote:

Originally posted by butchlambert:
How do you figure fluting stiffens the bore?
Butch

I don't understand how removing metal can stiffen a bore, either. In the case of fluting, it can retain near the same stiffness with slightly less weight. Biggest advantage of fluting is cooling, more suface area.....Tom

Check the ABS website(you can get there from the Rock Creek barrels web site via a link).

Carbon fiber works IF the fibers are put on the correct way.

Turning down a well made cut rifle is not problematic.

Done correctly, the end product will be axially and longitudinally stronger and stiffer. It will also transmit the heat away from the inner barrel instead of trapping it there.

First understand the physics/chemistry, then develop a system that puts the fibers on in a useful manner.

Fluting: suppose you have two Krieger barrels of the same weight. Suppose barrel A weighs 3#, and barrel B started at 5# but was fluted down to 3#. Both barrels weigh 3#. The barrel that started at 5# and was fluted down to 3# will be much stiffer than the barrel that was always 3#. It has a wider diameter overall.

LD

To the o/p, why?

A composite barrel will be heavier than the lightest all steel barrel, because you have to leave enough steel in the blank to contain the pressure, and then you're adding carbon fibre and epoxy.

Now if you were to compare same weight properly constructed carbon wrapped barrels with an all steel barrel by hanging aplying a force on the end of the barrel, you should be able to measure that the carbon wrapped barrel is indeed stiffer.

But the all important question is, will a carbon wrapped barrel be more accurate than a lightweight all steel barrel, and I think you'll find that in that department, the carbon barrels on average don't shoot as well. And really, that's all that matters.

You take the relatively simple process of taking a steel round stock, deep drilling a hole, rifling it then contouring it, and then add the processes of properly preparing the steel to get a good bond, apply resin, wrap the carbon fibres, then heat to cure the resin.

Each one of those added steps in the manufacture of the barrel is a chance for something to go wrong, and none of those processes do anything to improve the parent barrel.

Doesn't sound like something to do once or twice. I'd leave it to those who do it all the time. I've shot a lot of carbon-wrapped centerfire rifles and didn't find them particularly advantageous. But I have had an Accuflite carbon barrel on a Ruger 10/22 now for close to 10 years and I love it. It is competitive in 50BR matches in the hunter category and I out-score a lot of the unlimited guns.

Just be sure to get the barrel from ABS.

There is an article about that type of rifle on 6mmbr.com

It will be easy to retrieve from the archives.

Let them make the barrel for you; there will enough steel at the receiver end to chamber now, and set it back after the accuracy starts to go sour...

Back when I was priveleged to fly F-16s for the USAF/ANG the horizontal portion of the tail was carbon fiber in some pattern that I certainly didn't understand. That part of the jet was where the 10 gz's was generated. I asked an engineer from General Dynamics how many Gz's the tail could handle, "all I can say is more than twenty and less than thirty". Hoo boy.

Maybe what Doc was getting at with the barrel fluting is one a barrel of equal weight or a barrel that has the same diameter as the depth of the flutes either way you are talking about a thiner contour barrel. which would be more flexible then a thicker barrel. But if you flute the barrel you could have a barrel of the same weight as a thinner contour and be significantly more rigid. But just removing material does not make the barrel anymore rigid in terms of what it is used for in shooting.

kcstott ; That's correct I some times try and just skip all the gingerbread details and state obvious

facts .


Standard grade carbon fiber (T300, HTA, etc) have mechanical properties with out resin of approx. 3 - 3.5 GPa tensile strength and 230 - 240 GPa Tensile modulus.


Mechanical Properties of Carbon Fiber Composite Materials, Fiber / Epoxy resin (120°C Cure)
Fibers @ 0° (UD), 0/90° (fabric) to loading axis, Dry, Room Temperature, Vf = 60% (UD), 50% (fabric)
Symbol Units Std CF
Fabric HMCF
Fabric E glass
Fabric Kevlar
Fabric Std CF
UD HMCF
UD M55**
UD E glass
UD Kevlar
UD Boron
UD Steel
S97 Al.
L65 Tit. dtd
5173
Young’s Modulus 0° E1 GPa 70 85 25 30 135 175 300 40 75 200 207 72 110
Young’s Modulus 90° E2 GPa 70 85 25 30 10 8 12 8 6 15 207 72 110
In-plane Shear Modulus G12 GPa 5 5 4 5 5 5 5 4 2 5 80 25
Major Poisson’s Ratio v12 0.10 0.10 0.20 0.20 0.30 0.30 0.30 0.25 0.34 0.23
Ult. Tensile Strength 0° Xt MPa 600 350 440 480 1500 1000 1600 1000 1300 1400 990 460
Ult. Comp. Strength 0° Xc MPa 570 150 425 190 1200 850 1300 600 280 2800
Ult. Tensile Strength 90° Yt MPa 600 350 440 480 50 40 50 30 30 90
Ult. Comp. Strength 90° Yc MPa 570 150 425 190 250 200 250 110 140 280
Ult. In-plane Shear Stren. S MPa 90 35 40 50 70 60 75 40 60 140
Ult. Tensile Strain 0° ext % 0.85 0.40 1.75 1.60 1.05 0.55 2.50 1.70 0.70
Ult. Comp. Strain 0° exc % 0.80 0.15 1.70 0.60 0.85 0.45 1.50 0.35 1.40
Ult. Tensile Strain 90° eyt % 0.85 0.40 1.75 1.60 0.50 0.50 0.35 0.50 0.60
Ult. Comp. Strain 90° eyc % 0.80 0.15 1.70 0.60 2.50 2.50 1.35 2.30 1.85
Ult. In-plane shear strain es % 1.80 0.70 1.00 1.00 1.40 1.20 1.00 3.00 2.80
Thermal Exp. Co-ef. 0° Alpha1 Strain/K 2.10 1.10 11.60 7.40 -0.30 -0.30 -0.30 6.00 4.00 18.00
Thermal Exp. Co-ef. 90° Alpha2 Strain/K 2.10 1.10 11.60 7.40 28.00 25.00 28.00 35.00 40.00 40.00
Moisture Exp. Co-ef 0° Beta1 Strain/K 0.03 0.03 0.07 0.07 0.01 0.01 0.01 0.04 0.01
Moisture Exp. Co-ef 90° Beta2 Strain/K 0.03 0.03 0.07 0.07 0.30 0.30 0.30 0.30 0.30
Density g/cc 1.60 1.60 1.90 1.40 1.60 1.60 1.65 1.90 1.40 2.00
** Calculated figures

Fibers @ +/-45 Deg. to loading axis, Dry, Room Temperature, Vf = 60% (UD), 50% (fabric)
Symbol Units Std. CF HM CF E Glass Std. CF fabric E Glass fabric Steel Al
Longitudinal Modulus E1 GPa 17 17 12.3 19.1 12.2 207 72
Transverse Modulus E2 GPa 17 17 12.3 19.1 12.2 207 72
In Plane Shear Modulus G12 GPa 33 47 11 30 8 80 25
Poisson’s Ratio v12 .77 .83 .53 .74 .53
Tensile Strength Xt MPa 110 110 90 120 120 990 460
Compressive Strength Xc MPa 110 110 90 120 120 990 460
In Plane Shear Strength S MPa 260 210 100 310 150
Thermal Expansion Co-ef Alpha1 Strain/K 2.15 E-6 0.9 E-6 12 E-6 4.9 E-6 10 E-6 11 E-6 23 E-6
Moisture Co-ef Beta1 Strain/K 3.22 E-4 2.49 E-4 6.9 E-4
** Calculated figures

These tables are for reference / information only and are NOT a guarantee of performance
1 GPa = 1000 MPa = 1000 N/mm² = 145,000 PSI

These tables relate to only 2 of the many fiber orientations possible. Most components are made using combination's of the above materials and with the fiber orientations being dictated by the performance requirements of the product. Performance Composites Ltd. can assist with the design of components where appropriate.

Now with all that said ; When we find a way to make knitted multi walled Nano Tube structure

I'll have a barrel made from it as the metal will be unnecessary. Welcome to my world .

Perhaps I should call Burt Rutan or Sir Rich and inform them ,I possibly miscalculated and give back

the Ansari X-Prize . Will they be surprised !... Are there any current record holders using

Carbon wrapped barrels ?.

For now I'll use Schneider or Lija barrels ; See you on the range ...