If Nerf Hyper rounds are 13-14mm diameter, then it stands to reason that with minor modifications the Sportsman would be able to fire them. With a massive hopper it may make for
NERF HYPER lineup fires at 110 fps with 3-4x round capacity - 9to5Toys
Nerf Hyper Mach-100 Fully Motorized Blaster E8911 - Best Buy