Charles hat geschrieben:Der Mod meint, ich bin überall dabei und gebe meinen Senf ab, dabei habe ich ihm geschworen, daß ich nicht mehr so viel OT quatschen tu. Selbstbeherrschung ist derzeit null bei mir
Im Ernst, mir ist eigentlich nicht klar, was die Carbon Ummantelung überhaupt bringen soll
TECH REVIEW -- The Science of Carbon Barrel-Wrapping
Carbon-wrapped rifle barrels are not new to the gun industry but until now, most of them have been sleeved instead of individually wrapped using a helix-pattern matrix, the ABS method. This can create problems, as ABS President Mike Degerness explains:
Carbon-wrapped barrel"Many old-technology composite barrels rely on tensioning a composite sleeve over a tiny barrel liner. There are flaws in this approach. When steel is heated, it expands; carbon shrinks when heated. Any heat changes the amount of tension in the barrel and as a result the harmonics change too. Our patented method of tuning the barrels by manipulating the helix angle of the fiber placement isn't heat sensitive."
With old-fashioned carbon-sleeved barrels there was a problem because the carbon acts as an insulator, interfering with the transfer of heat away from the steel core. The old-school carbon barrel sleeves perform poorly because they are made with polyacrylonitrile (PAN) fibers. With PAN fibers, heat tends to follow the fibers and will not cross from fiber to fiber. Depending on the type of steel used, common rifle barrels have a thermal conductivity around 20 W/mxK, while a wrap using straight PAN fibers has a thermal transfer coefficient of around 19 W/mxK. This similarity in thermal transfer rates does very little to dissipate the heat of the steel core. This is the underlying reason for the poor performance of many of the early attempts to apply carbon-wrap technology to rifle barrel. Heat would not escape easily through the carbon sleeve, so the steel barrel core didn't cool adequately.
barrel cooling testMatrix Technology Aids Barrel Cooling
To overcome this material problem (poor heat dissipation away from steel barrel core), ABS developed a matrix of materials that includes chopped pitch fibers similar to those used in the brake pads for racing cars. This matrix, combined with an epoxy that can withstand 500? F, provides an extremely ridged structure with a thermal transfer coefficient approaching 700 W/mxK -- 35 times higher than that of "old-fashioned" PAN-fiber carbon sleeves.
So what does that mean for the shooter? Quite simply, ABS has figured out a way to make their carbon-wrapped barrels cool faster than first-generation carbon-sleeved barrels. In fact, the ABS barrels cool up to 300% faster than all-steel barrels. Thermal tests conducted at the University of Nebraska College of Engineering showed that an ABS carbon-wrapped barrel will cool much faster than a steel rifle barrel of matching profile.
Mike explains: "We recognize that heat management is a critical element of building a better barrel. Carbon composite barrels built with ordinary fiber grades have a reputation of insulating heat. We use a patented method of applying a thermally conductive matrix that conducts heat 372% faster than steel." barrel cooling test
If you look at the charts at right (from the Univ. of Nebraska lab tests), you can see that the ABS carbon barrel actually sheds height faster than an all-steel barrel. Also notice that, on the ABS carbon barrel, the muzzle stays cooler than the chamber. By contrast, on the all-steel barrel, when the chambered reached 190° C, the muzzle reached 262° C! That all-steel barrel got very hot at the end, something that can degrade accuracy.
[Editor's Note: Tests by Berger Bullets indicated that excessive barrel heat in the last few inches of barrels was one of the most common causes of jacket failure. Barrel tip heat caused problems even when bullet rpm was "moderate".]
Warnschuss hat geschrieben:Und was jagt man mit der .338 Lapua Magnum? Gorillas auf 800m?
Varminter hat geschrieben:Zum Beispiel Maral und Steinbock in Kirgisien oder schwere afrikanische Antilopen wie Oryx und Kudu auf ein "bisserl weiter".
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Varminter hat geschrieben:Wer sein Gewehr bei der Auslandjagd selber schleppen musste, versteht mich, da zählt jeder Gramm weniger Gewicht.
