Around here I see lots of high end top singles (and why not, MD is the home of Silver Seitz). So if you think about it, you will see that gun makers like Seitz, Ljutic, Alferman, Bowen, and DeVault do not make an "unsingle". Further, considering how many shooters use guns like TM-1, 90T, Model 12, 870, BT, 1100, 390, etc, I would say that the unsingle guns are out numbered by a large margin.
Meanwhile, a gentleman named Keith Ditto shoots all three games with an MX-8 over/under and his averages are amongst the best in the country (and he is not a full time shooter).