|For an overview of pulse rifles, see pulse rifle.|
While named similarly to the pulse grenade and pulse rifle prototype, it is not actually an electromagnetic pulse weapon, but instead shoots electrical pulses effective against living targets as well, not just electronic devices.
The most expensive weapon in the game at 17,500 caps, the YK42B pulse rifle has the highest damage per shot of any rifle in 23rd century post-nuclear Northern California. Combined with its Weapon Penetrate perk, this makes it the most armor-piercing energy weapon in Fallout 2, dealing heavy damage against even the most high-tech protective gear.
The YK42B pulse rifle does a whopping 66 Hit Points of average damage against unarmored foes. Against medium-heavy and maximally heavy personnel armor, it averages 33.24 and 22.54 HP per shot, respectively. This weapon's critical damage is almost unparalleled, with critical hits to the eyes capable of surpassing 300 HP and averaging well over 150 HP against most enemies.
For a character with an average Critical Chance (5%), eye shots from this weapon do more average damage against the heaviest armor types than what point-blank bursts from most machineguns do, at the same action point cost.
Despite its strengths, the YK42B is hardly an all-around weapon suitable for any and every tactical situation. Its range of 30 hexes is shorter than those of the other high-end rifles, preventing the player from immediately targeting the farthest enemies in some encounters that occur on desert plains. Secondly, unlike the other high-end rifles, the YK42B lacks both the Weapon Long Range and Weapon Accurate perks, thereby requiring an extremely high skill for accurate aimed shots to be possible at its maximum range.
Thirdly, as an electrical pulse weapon, the YK42B does little non-critical damage against floaters, which are a fairly common enemy in New California and highly resistant to electricity. armor-piercing critical hits circumvent this problem though.
On the other hand, the YK42B pulse rifle (together with the alien blaster) is the most effective single-shot weapon against Frank Horrigan, whose only weakness is his low resistance to electrical damage.
- It may be found after gaining access to the Brotherhood of Steel bunker in San Francisco in one of the lockers on the lower level.
- From level 19 and onward, some of the robbers found in the mountain caverns random encounter carry one.
- Many Enclave soldiers on the Enclave Oil Rig, such as Granite, carry one.
- Scoring a killing blow on an enemy with either a critical hit, Bloody Mess trait or simply a powerful enough attack will reduce them into a pile of ash. Thus, any items they were carrying get scattered on the ground nearby and have to be picked up one by one. This can be avoided by turning the violence level down in game settings, which disables particularly graphic death animations.
- The YK42B, unlike the YK32 pulse pistol, doesn't fire a visible purple projectile.