I own four 20ga slug guns all rifled barrels all using Remington Accutip 3", they each have there limits.

Savage 220f, no doubt I would take a shot at 200 yds plus
H&R Ultra Deluxe, 175 yd limit
Remington 11-87, 150 yd limit
Mossberg 500, 125 yd limit

Remember all guns may shoot well, but they have their limits