Got to shoot the FN 303 at a recent conference but unfortunately, they didn't give us the range to shoot from a distance (that range was reserved for the rifles).
The 15 round drum magazine isn't hard to load but you do have to maintain tension on the spring as you push the hopper forward to load a round. There is only one "open" port and tension will hold that 15th round into place. Granted it's not as fast to reload as a regular paintball, but the round is not your ordinary paintball.
The rounds are available with various color paints, OC (oleoresin capsicum) and to be released soon, a luminous round (see your perp in the dark). There's also a training round that contains a glycol based substance. It still has bismuth so as to retain the flight characteristics of the other rounds. They appear to be like a shortened Minie ball (Civil War era bullet) but like Owen says, they contain 8 grains of Bismuth in the front end. This is not something you want to whack your friends with in a "friendly" game. The lower portion of the round contains the paint marker itself. There are small fins on the round that appear much like the Brenneke shotgun slug. This is touted to give the FN303 the superior accuracy and range over the normal paintball. This is almost akin to the old smoothbore muskets v. the "rifle-gun" of the Revolutionary War, War of 1812 and the Napoleonic Wars.
The gun is fully ambidextrious and the magazine release is located in front of the drum magazine. The safety is a paddle that is within the trigger guard and you merely flip it forward to put it in the "fire" mode. The gun has also been adapted for the AR-15 (in lieu of the grenade launcher) and the new FN 2000 bull pup rifle.
Overall, a nifty "less-lethal" addition to police inventory. Since it can be mounted on an AR, the officer using it can readily transition from "less-lethal" to lethal should the perpetrator fail to respond to lesser force. That means the "less-lethal" officer doesn't have to rely so much on a back-up officer or go through a "transition" drill from "less-lethal" to lethal.
Vigilantibus et non dormientibus jura subveniunt. Molon Labe!