speedy
NES Member
Have heard people argue that they would not buy a barrel made with 4140cm (chromoly) because it is not 4150cmv. The argument is that the 4140cm is not bad it just can’t shoot heavier than about 62g bullets. And the 4150s AR 15 barrels are not as susceptible to gas port erosion as the others, i.e. 4140cm(chromoly).
My understanding is that the 4150cmv steel contains more carbon than 4140cm. 4140cm has about 0.4% carbon/unit mass and 4150cmv has about 0.5% carbon/unit mass. Not a big difference. But, as a result the 4150cmv will have a higher hardness (and brittleness) after heat treating, while the 4140cm will be a bit more malleable. I can see this being an advantage on full auto AR15’s, or military weapons of course (which is used). But, most civilian barrels for hunting, plinking, and Ar’s are made of 4140cm.
What are your thoughts?
My understanding is that the 4150cmv steel contains more carbon than 4140cm. 4140cm has about 0.4% carbon/unit mass and 4150cmv has about 0.5% carbon/unit mass. Not a big difference. But, as a result the 4150cmv will have a higher hardness (and brittleness) after heat treating, while the 4140cm will be a bit more malleable. I can see this being an advantage on full auto AR15’s, or military weapons of course (which is used). But, most civilian barrels for hunting, plinking, and Ar’s are made of 4140cm.
What are your thoughts?