I still think that the most important variable is the shooter.
Yes, it always will be.
This is the Shooter's Triangle. The shooter is the foundation of it. He is also the most volatile element of the three. The best rifle and cartridge will not perform if the shooter is unpracticed. Great shooters can turn in creditable performances with so-so ammunition or untuned rifles, but the best rifle and ammunition cannot change a so-so shooter into a sharpshooter.
Like the fire triangle, take away any one of the sides and good shooting is impossible.