The Beretta Px4 Storm is a semi-automatic pistol manufactured by Beretta of Italy. It is the only non-92 Beretta used by McClane, as he no longer used the Beretta 92 as his main sidearm.
The suppressed Beretta Px4 Storm pistol was used by Thomas Gabriel's henchman Russo to kill the two MP guards at Woodlawn. Later, Russo used the one without the sound suppressor at John McClane and Matt Farrell at the control room of one of the cooling towers, but after McClane defeats him, he takes the gun after losing his SIG Sauer P220 pistol earlier in the film.
McClane used the Beretta Px4 Storm to fire at Rand in the cooling tower. He also used it to kill Robinson, Trey and one of Gabriel's last henchmen. After Emerson wounds McClane, Matt Farrell later takes it and uses it to kill Emerson.Irina Komarov is seen pulling a Beretta Px4 Storm Subcompact when she supposedly betrays her shocked father, Yuri Komarov. She holds it to Komarov's neck and leads him to a Hind helicopter where they fly away to Chernobyl.