While most Starfleet officers had received training in the use of EM weapons, by 2151 the EM-33 began to be replaced aboard Starfleet vessels with the phase-pistol, Enterprise NX-01 being one of them. (ENT: "Broken Bow") One of the disadvantages of the EM-33 was the need to compensate for particle drift, making the transition to the next generation, point-and-shoot phased pulse weapons difficult for some Starfleet personnel. However, according to Jonathan Archer the two weapons still handled roughly the same. (ENT: "Sleeping Dogs", "Fight or Flight")