Quote Originally Posted by Gnoman View Post
There's also the "what is quality" factor.

For an example, there was a firearm from the mid-19th century that saw service in the American Civil War that was fairly accurate (minute of angle at 500 yards) even by the standards of today, and absurdly accurate in comparison to the weapons of the era. It was not adopted on a large scale by any army, although some (like the Confederacy) used it in a small specialist role, and was a major commercial failure. This is because the weapon was obscenely expensive to produce with the available technology, and fouled much quicker than other rifle muskets. Was this a quality arm or not?

Weapons (like all tools) evolve to suit the needs of their era, and sometimes that evolution will produce models that seem "inferior" to those that came before.
Sounds like a similar reason that apparently lead to the ubiquity of the AK47 and various knock-offs: it wasn't the 'best' rifle around, but it was cheap and easy to make in large quantities, durable and easy to maintain.