The Glock 17 (Beretta 92FS in the HD Edition), also known as the 9mm Pistol, is a weapon featured in Half-Life and its expansions. The standard issue weapon used by the Black Mesasecurity guards, it is one of the most commonly used weapons in the series. It can be fired in either semi-automatic or rapid fire mode.
In Half-Life, the Glock can first be found in the chapter Unforeseen Consequences; it can be obtained by killing the first seen security guard or dropped by a dying guard before the player exits the Anomalous Materials laboratory, or kill the security guard who is shooting the zombies where the player meet the security guard. In Residue Processing, it can be retrieved from a security guard being eaten by a Barnacle.
A suppressor-equipped Glock is also used by female Black Ops, but cannot be picked up by the player.
If fired in semi-automatic mode, the Glock is one of the most accurate weapons in the game. While it does little damage per shot, it has good accuracy even after multiple shots in a row.
Because of its accuracy, it is best used at long range. Most enemies have poor accuracy at long range, which puts the player at a major advantage.
When firing at long range, aiming for the enemy's head is advised, as headshots do triple damage. This works very well against enemies that have high health, such as the Bullsquid.
This weapon shares ammo with the MP5, which makes it very easy to find ammo for this weapon throughout the game.
The Glock is one of the few weapons that functions underwater, therefore it is a good choice to use against the Ichthyosaur if one wishes to conserve Crossbow ammunition. However, it takes longer to kill an Ichthyosaur with the Glock than it does with the Crossbow.
Rapid fire mode
The rapid fire is activated via secondary fire.
It is best used when an enemy unexpectedly appears while firing at long range. Its rate of fire is fast enough to kill an enemy at short range without too much trouble.
It also works well as a makeshift SMG before the player obtains one. However, they should make sure to reload often, as this mode quickly eats up ammo, and this mode is even less accurate than the SMG.
Even if one shot is fired in rapid fire mode, it will be less precise than in semi-auto mode, thus making the rapid-fire mode useless for precise shots. This does not apply for Opposing Force, where accuracy remains unaffected.
The rapid fire mode cannot be fired when underwater.
Behind the scenes
The Glock was originally to have an attachable suppressor. Scrapped in the final version, the attachment and detachment animations are still in the model file. It is unknown where it would be obtained. As the suppressed Glock is used by female Black Ops as their primary weapon, it is likely it was to be acquired through killing one.
A well-known mod called They Hunger added a suppressor to signify that it was it semi-automatic mode. The player would remove the suppressor to fire in rapid fire mode
One of the early Half-Life demonstrations shows that the Glock had an early magazine count of 12 rounds, had the suppressor attached by default and required the slide to be racked after every reload.
An early texture for the Glock featured in the Half-Life SDK files shows it was first to be a Glock 18.
Half-Life Day One's Glock 17 uses a higher resolution texture.
In Half-Life and Opposing Force, a small glitch with the Glock exists: it can be reloaded at any time, even with a full magazine. The most likely reason for this is because the magazine size of the Glock was reduced from 18 to 17. Furthermore, although the gun retains the 17 bullet magazine in the retail version of Blue Shift, the glitch cannot be performed.
The real life Glock 17 doesn't actually have a selectable fully automatic mode; some media use modified versions to stand in for the Glock 18 (the first true full-auto Glock, which is selectable between semi-auto and full-auto), but these modified weapons can only fire in full-auto, at a much faster rate than the rapid fire mode in-game (about four times faster).
The Glock 17 has a different firing sound when used by NPC security guards.