To be considered a "sniper rifle," the rifle has to be capable of holding a MOA (minute of angle), regardless of barrel weight, length, twist, or optics. But, most rifles that can do that have a heavy free-floating barrel, the perfect length and twist for the nodes and antinodes, and a good set of optics.

It doesn't matter what your effective range is, just that you can hold a MOA. Basically, for ya'lls purposes, that would be 3 shots in 1" at 100 yds. If your rifle can shoot every round you fire from 100 yards into a 1" pasty, you can declare your rifle a "sniper rifle" if you so choose.

Has nothing to do with the shooter, because you can take the 40, put it in a vise and it will easily hold a MOA, but throw it in someone's hands that doesn't know what they're doing with it, and it will look like a shotgun pattern. That doesn't make the rifle not a sniper rifle, that just makes the shooter unqualified.