Originally Posted by
MistWolf
Manufacturers who have made the leap from "hobby" to "professional" have the whole package, starting with being professional right from the start.
Folks act like 4150 CMV is the only steel worthy of being used to make barrels. 4140 has been used for decades to make good, even legendary barrels. It's what Steyr used to make barrels for their StG58 which are known to be the best FAL barrels made. Even 4130 has been used with great success. While 4150 CMV is one of the top steels, it doesn't make 4140 or even 4130 barrels garbage. Can anyone here say they can actually see a difference in accuracy, reliability or durability between 4150 CMV and 4130 CM?
One of the few places a manufacturer can actually exceed mil-spec is by developing a manufacturing process for bolts that eliminates the need for HPT. HPT tests bolts and barrels at pressures beyond what they are designed to take. Each barrel and bolt has a limited, but unknown, over-pressure events it can withstand before it fails. Each time a bolt or barrel is HPT tested, that finite number is reduced by one. HPT testing can also start a failure within the part that is still within allowable limits, or even below detectable limits, yet set the part on the path of failure.
Some will insist a bolt must be made of Carpenter steel and must be HPT tested, yet it's interesting to note that KAC does neither