Latest are German Lothar Walther barrels. They are button rifled, so not cold hammer forged.
http://youtu.be/J16nVcXP_eAAbout the new Czechpoint barrel maker:
Rifle Barrel Blanks
The production of barrel blanks at Lothar Walther is accomplished in state of the art facilities. Our rifle barrels are produced using button rifling. We were the first to use this method and it has been in use since 1925. Our materials are specifically engineered to be used in our process. Our Normal Steel, what every one calls "Chrome-Moly" is a special alloy which is very fine grained. It will perform in all situations and will generate phenomenal accuracy. Our Stainless Steel is of a very special type which will give longer barrel life and can be used in all contours. It far exceeds the capabilities of 416R. We manufacture calibers which range from 17 caliber to 600 caliber. Most calibers are stocked in both normal steel and our stainless steel. The charts below give our standard stock barrel blanks. Even with this large selection, there are still many types of barrels which are not shown. There are straight octagon barrels in some calibers. Black powder barrels are available. If you do not see what you are looking for, give us a call, we may have something special hidden away just for you.
http://www.lothar-walther.com/359.phpAnd here's the CHF process -- cheapest form of production at high volumes, most expensive at low volumes...:
http://youtu.be/aCMzyNHkjpkhttp://youtu.be/8pzL5h2cl80A good read on barrel types if interested:
http://www.firearmsid.com/Feature%20Articles/RifledBarrelManuf/BarrelManufacture.htmWorth noting that while these 16" barrels are a great change from the NFA restricted 15" barrels (especially when considering that the permanent spot welding of muzzle devices may temper the 15" CHF barrels thereby negating CHF's strength advantage at the critical muzzle location), the CSA VZ58's premium price point doesn't necessarily lineup with their manufacturing decisions... So essentially the difference between CSA and Czechpoint barrels is now just chrome lining (Green Mountain barrels are button rifled as well)... And the two mag 922r compliance parts remains an abomination and needless risk to convey to their customers... Put in a CNC Warrior trigger (not that glass filled nylon bs) and a US Grip or Muzzle Device, and a CNC Warrior piston. And call it done.
And fwiw, CHF really only matters for full auto rifles when the barrel will be getting really hot regularly. CHF results in a slightly more dense barrel, absorbing more heat per same width/diameter/volume of material so it helps to avoid cookoffs of in chamber rounds, a problem for ARs in particular... [note: mass/weight does/will change -- a CHF should be heavier per unit of volume than a non-CHF barrel.] The denser material in a CHF barrel also hardens both the lands and grooves of the barrel, which is also especially important under high heat full auto fire as it results in less material removed with each shot... And the denser material, conceptually at least, should result in less width/diameter being removed with each shot, though probably an equivalent amount of molecules removed w/ each shot.
And here's a great read on why nitriding is superior to chrome:
http://www.akfiles.com/forums/showthread.php?t=186658I agree with Mr Fuller.
Nitrided barrels are where it is at.
The barrels can be cut or button rifled to the correct twist and diameter, and then the metal gets case hardened, and nitrogen infused.
It results in a exceedingly strong barrel. It resists corrosion, doenst change internal diameter, withstands higher temperatures, and lowers the coefficient of friction against the bullet.
With all the new techniques in rifling, a radial land/groove, nitrided, faster twist AK barrel would be the cream of the crop.
Following on with what jim stated:
The differences in nitriding and chrome lining are vast. When a east block AK barrel is hammer forged, it does result in a more uniform grain structure. However, the bore is oversized in the CHF process, because when the chrome lining is applied, its builds onto the surface. (somewhere between .2-.6mm thick)
Also, when something is chromed, its a electro plating process. It never applies itself uniformly inside the bore. It deposits itself all over, and there will be high and low spots of more chrome/less chrome inside the bore. These hills/valleys are minor, but it is a factor.
ak barrels for example, are hard chromed for extreme wear situations. They're applied quite thick. This thicker application ends up amplifying surface defects even further, which requires additional finishing to try and smooth out. When machining these barrels shorter (like jim stated) the chrome lining has a tendency to chip.
But aside from that, it was a excellent idea to improve barrel life and corrosion resistance 50 years ago.
However, now a barrel can be cut or buttoned, with the exact internal bore diameter, and land-groove width. Then it can be nitrided, and the dimensions do not change. The land/groove width stays uniform from throat to muzzle, and the bore diameter doesnt change. The barrel is case hardened down, and nitrogen is rapidly absorbed and retained within the case layer. Nitrogen inhibits corrosion. This case layer is part of the steel, so when machined or super heated (full auto), it doesnt separate from the barrel, because IT IS the barrel.
Nitriding
doesnt "crack" under extreme heat
doesnt chip or flake
doesnt allow separation due to corrosion (oxidation under chrome, will lift the chrome off)
doesnt change any dimensions
Increases rockwell hardness
Drastically increases oxidation resistance
lowers friction inside the bore.
Whats not to like? Its a huge innovation to the firearms world.
Granted, its not "original" to the weapons platform, but its sure as !@## infinitely better, and much cheaper. I'll take performance over aesthetics anyday.
*Also, nitriding is cheaper and doesn't have all the environmental/pollution concerns as chrome either -- and on some of the thinner US "chrome" barrels, when nitrided the nitriding displaces the chrome in entirety.
^A-Plus. I could not have stated it better.^
Cut rifling is the most accurate process and provides the fine detail for corners, fillets, and rounds. The finished land and groove surfaces are the same density as the barrel material. Now; it is a slow process.
Button rifling is quick and fairly accurate. It is a burnishing operation moreso than a broaching operation and leaves a more dense "skin" for the lands and grooves. Now; it is hard to keep fine details as exacting corners, fillets, and rounds as the finished rifling is dependent on the plastic flow of steel.
Cold hammer-forging should produce lands and grooves that approach button rifling in regards to accuracy. Again; it is dependent on the plastic flow of metal. The advantage is the more dense "skin" at the lands, grooves, and chamber as well as the more dense "skin" on the exterior of the barrel. The parent metal is also a bit more dense as well.
Nitriding or Meloniting - whichever term you choose for this process is a great leap forward. The only requirement is that the steel must be of an alloy and minimum carbon content that responds to this treatment. It is essentially a low-temperature (1,100 Fahrenheit) case-hardening process that does not require a quench.
This process was perfected many decades ago but is fairly recent with its widespread application to barrels. I remember when we had to select a steel alloy that was "nitridable" for certain parts and had to use certain mill alloys that were formulated to respond.
I am impressed with its performance. The only caveat I see is that a barrel must have journals finished to size before one begins assembly as the skin is more than "file hard" and a few 0.001"s deep. It is certainly less "sticky" and interference-fit parts are easier to press on, and easier to clock.
