Hi. I ordered a AK74 with a PSA 4150 CMV barrel however it seems to be black on the inside. I wanted to know if this is supposed to be the case. The barrel isn’t stamped with what kind of barrel it is on top and while I contacted PSA customer service about this, I was wondering about more details. Any thoughts.
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Yes. My understanding is barrels are treated after the grooves and flats are cut.
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Everything I have read about the ak-74 is that all the barrels are 4150 CMV Nitride inside and out. I haven’t seen one of these PSA ak-74’s in person, but all the reviews I’ve seen and read from people owning them and reviewing them here on the PSA forums/Reddit seems like everyone has gotten them with the inside and outside finish being Nitride.
That is correct. For barrels to be nitrided they have to be submerged.
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Just wanted to verify. I figured CMV chrome lined would have a chrome line appearance, but that’s just me I guess.
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Yeah if they were chrome lined inside, you would be pretty easily and clearly be able to tell just looking at the front trunnion and see the silver/gray coloring of the chrome lining. Or if ya really wanted to be sure, remove the slant break/muzzle device and you’ll quickly be able to see the nitriding at the end of the barrel.
Pretty sure they don’t have a chrome lined 74 sku … they are listed as Chrome-Moly Vanadium not chrome lined… the fn barrels and psa in house chrome lined barrels are usually clearly listed in the description.
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And are CHF.
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Chrome Moly Vanadium? What separates that from chrome lined?
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I’ve never worked with metals and don’t really know enough… Chome lined is a coating on the bore of the barrel itself, not a build material. Chromoly is the build material itself. The difference between the two in realistic terms is miniscule, but it is said that an unlined barrel is slightly more accurate, while a lined barrel is more resistant to corrosion and wear.
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Except Nitride has changed things. It used to be chrome lined vs phosphate or blued. Nitride actually hardens the metal without the thickness variances of chrome lined. Many folks say it is better because of that.
Reality is unless you shoot thousands of rounds a year you wont outshoot the barrel.
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Nitrided vs. chromed cylinder sleeves on piston powered aircraft, it;s a give and take everywhere.
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41xx Chromemoly steels:
Chrome-plating as a liner on military gun barrels is more for corrosion and heat-resistance than wear; although a side benefit of chrome lining is it’s probably twice as hard as the underlying steel.
But so is Nitriding, at a Significant Savings with no downside to the finished product.
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I would say a nitrided barrel would also be more accurate than chrome lined. Heres some info
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exactly so, and thus many also say the nitride process has made better barrels than having the chrome lined / phosphate or blued barrels as its more accurate because of no lining, and more durable because the nitride holds up better.
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