I see this all the time when related to defensive type weapons. You take a firearm that functions flawlessly and start changing out parts to make them fit with the precision of a Swiss timepiece.
Why does a person take a weapon designed function under adverse dirty conditions and hit a man sized target at 5-25 yards using any ammo you might feed it and turn it into a tight fitting firearm that can hit a gnat at 50 yards but will jam when using non spec ammo or when dirty?
They forget that maybe the designer actually meant for the weapon to be so loose fitting that a grain of sand could not stop it from operating. Do you really need a precision fitting 1911 that can hit flies at 50 yards? One that fits so tightly that it couldn't rattle even after 20,000 rounds have been put through it?
I have seen numerous firearms improved to the point that they are super accurate precision arms. To get there they traded reliability and the ability to quickly do repairs and keep it in action.