UT Eightball
"UT_Eightball" is the name used in the UT code for the Rocket Launcher. Originally the Rocket Launcher was evidently going to again be called the Eightball gun as it was in Unreal 1, but it was then changed to Rocket Launcher.
The Rocket Launcher uses RocketPack as ammo class and RocketMk2, UT_SeekingRocket and UT_Grenade as projectile classes. The projectile classes are hardcoded in the script, so changing them in the default properties has no effect.