The nut behind the trigger matters too.
Yup and is the biggest factor.
That has nothing to do with building an accurate rifle either.
Like folks that say 'A 6 inch revolver is more accurate than a 2 inch revolver'
Barrel length has nothing to do with it, all they are commenting on is that they can shoot a longer barrel better. It doesn't mean that one is inherently more accurate than the other.