The Semi-Auto Rifle is not a usable weapon in the singleplayer campaign. However, in a cutscene two Fireflies armed with semi-auto rifles approach Joel as he is trying to resuscitate Ellie. One of the Fireflies then uses the butt of his rifle to knock Joel unconscious.
The Semi-Auto Rifle is a reliable mid-range killer that is unlocked at the start. It starts out with seven rounds and the non-upgraded magazine holds eight. It costs two loadout points to equip. Versatile and powerful, it is easily the best weapon for any beginning player and is still a reliable choice for experienced players.
It is able to be silenced with a suppressor, using four loadout points to equip.
When upgraded, its Reload Speed, Magazine Capacity, Rate of Fire, Starting Ammo, and Accuracy are increased:
- Upgrade 1 costs 400 parts.
- Upgrade 2 costs 800 parts, this gives a player with a fast trigger finger the ability to interrupt melee attacks effectively.
- Ammo costs 220 Parts for four rounds.
The Semi-Auto Rifle is an effective weapon at medium and long ranges. It is much more accurate when fired from a stationary position, able to down in three hits or two the head, and its fast rate of fire can often down unaware players before they can find cover. However, it takes two shots to execute a downed enemy. Therefore, its damage output is identical to that of the Revolver; in fact, the only difference when fully upgraded is that the semi-auto can be silenced and has larger magazine.
The Semi-Auto's only real weakness is close range combat; weapons with a rapid rate of fire such as the Burst Rifle or weapons with a huge amount of wobble in the enemy's reticle such as the Full-Auto Rifle can often beat the Semi-Auto Rifle in close quarters. Also, the amount of starting ammunition is very low when compared to other long guns means that every shot must hit the target in order to get the most out of this weapon early in the game.
- The Semi-Auto Rifle's appearance is based on the Ruger Mini 14. The in-game rifle looks more modern with a dark finish and appears to have a "Butler Creek" folding stock.
- The Semi-Auto Rifle was actually obtainable in the single player campaign during The Firefly Lab. However, Naughty Dog nixed the idea. Regardless, it is still possible for the player to obtain the rifle via hacking and the ammo boxes the player collects for the Assault Rifle still have the Semi-Auto's image on them.