The phase rifle was a standard-issue directed energy weapon in use by Starfleet and Earth's MACO forces in the mid-22nd century.
In 2151, a Starfleet security officer carried a phase rifle into Cargo Bay 2 while investigating the presence of a strange alien lifeform with Captain Archer and [[Commander Tucker aboard the Enterprise (NX-01) . The security officer attempted to use his phase rifle, which was set on stun, to fend off the creature when it began to attack them, but was distressed to find out that the weapon had no measurable effect on the creature. ENT Vox Sola}
In 2153, two security officers accompanying Lieutenant Reed attempted to use phase rifles to fend off two Tarkaleans who had been assimilated by the Borg, but were unable to penetrated the Tarkaleans’ personal force fields. ENT Regeneration
The MACO’s phase rifle fired blue pulses of concentrated energy at its target and was capable of multiple settings. The observed power settings range from stun, to kill, to a high-power kill setting capable of blasting a perfectly symmetrical hole over an inch in diameter through a Human torso. ENT The Augments Power levels could be changed by manipulating either of a pair of circular dials mounted on either side of the weapon. Rotating the power level selector forward / away from the user appears to increase the power level. ENT In a Mirror, Darkly
The weapon featured a tubular stock, vertical foregrip, and a multifunction scope that could be retracted into the body of the weapon. There may also be a sniper variant, though it is unclear whether or not the sniper / designated marksman version is a distinct weapon system or a standard MACO phase-rifle with a retractable barrel or separate barrel attachment. ENT The Xindi
While extremely powerful when set to kill, its stun setting appeared to be somewhat ineffective against species that were more physically resilient, such as enraged Vulcans, Xindi-Reptilians and the Augments. ENT Impulse Rajiin Borderland
Phase rifles were in use as late as 2161, when a team of MACOs utilized the weapons during a mission to rescue Talla, the daughter of Shran and Jhamel, from a group of alien kidnappers on Rigel X. ENT These Are the Voyages...}})