Rifled BBs - Someone tried making rifled BBs in Japan 20 years ago. They looked like Civil War bullets, round nose, back end hollow, outer back end had rifling groves and muzzle loaded. Didn't work too well for some reason.
Finned BBs - Another one that was made was a BB with a short stem on the back with fins. Very, very accurate but range was no greater than a standard BB. These were used in bolt action rifles only and muzzle loaded.
Rifled Barrels - Great for pistols. Accuracy is very good up to 10 yards. Beyond 15 yards they suck.
To get the range you're looking at you need a velocity level of about 450 fps. I played that in Japan with 0.36 BBs. I loved it! Average engagement range 40 yards, max effective range 70 yards max range 90 yards. Bush offered no sanctuary, you found real cover. And when you were shot at, BBs passing by your head buzzed like a bee, vegetation was scattered in the wind, bark on tree flew into the air and dirt burst from the ground. It definitely added to the pucker factor. [smilie=armata_pdt_12.gif] Two thing you did to protect yourself, make sure you had a face mask and never charge a position.