The following weapons were used in the television series Ascension:
Ruger Mk II
A bullet taken from a body is described as a ".22 short". While the Mk II can fire this caliber and size, it is not specifically chambered for it, and as such the weapon would not cycle independently. This may explain the fact that the weapon does not fire later on when it is used by Stokes, although it is said that the safety was left on, although no one who made that statement had gotten a close up look at the weapon. It is also not 100% certain this was the weapon used to fire the ".22 short" round.
The appearance of this weapon on board the ship could be anachronistic, as even though the show is set in the present day, the ship was launched in 1963, and the Mk II didn't go into production until 1982. However this may be explained by the "twist" at the end of the first part, which I will refrain from posting as some may not have seen it quite yet.
A security guard is seen wielding a Glock 19 during 'Part 3'
A security guard is seen wielding a SIG-Sauer P226 during 'Part 3'.