Shotgun,
There's another way. The guys that designed the Tiberius rifled around above, are the same guys that designed the "Perfect Rounds". Their capsule is not actually gelatin based like a typical paintball (but still biodegradable iirc, a big deal when playing at MOUT sites). Perfect rounds literally were perfect, to a microscopic level, they were just expensive as hell. I think the Tiberius round uses the same material.
If they could use that material and dimple it, I think we'd see something really cool. The flaws I see with the Tiberius round are actually the spin, since a spinning, ballistic object loses forward speed much faster than rotation, you get an "overspin condition" which causes instability. Plus you get extra drag from the open rear end, which is a large gap compared to the ballistics of a real bullet. I really want to see somebody lay it side by side with a regular paintball, and do a real comparison, calculate drag coefficient of it, range test on identical markers, all that.