In "Hoosier Daddy" (S01E02), Luis Cruz (Steven Michael Quezada) pulls out a Stainless Taurus PT100 AFS pistol with gold accents during a drug negotiation gone bad.
In "Pilot" (S01E01), Frankie Santoro (Al Sapienza) uses a suppressed Smith & Wesson 910S. There is a continuity break in that the one he later carries in the room is a older Model 5906.
Smith & Wesson 5906
Frankie Santoro's (Al Sapienza) suppressed auto becomes a Smith & Wesson 5906 with old style fixed rear sights in the "Pilot" episode. In Season 1's "Trojan Horst" several assassins use 5906s with Novak sights.
Bryco M59
In "Pilot" (S01E01), Felicia Santoro (Kathrine Narducci) holds a Bryco M59 pistol in silver finish, until Marshal Shannon disarms her.
Jericho 941 R
In "Trojan Horst" (S01E04), the assassin disguised as the 'wife' (D'Nette Pennington) uses a stainless Jericho 941 R Pistol.
Steyr SPP
In "Iris Doesn't Live Here Anymore" (S01E07), the street gang member uses a full-auto modified Steyr SPP pistol to kill the boyfriend's witness.
"Non Gun" Beretta
In "Good Cop, Dead Cop" (S01E09), Robert Eps (Jason Wiles) uses a "Non Gun" Beretta to threaten a corrupt cop in Chicago.
Revolver
"Non Gun" Revolver
In "Good Cop, Dead Cop" (S01E09), a "Non Gun" Revolver is pulled by a corrupt cop in Chicago.
Rifles
M4A1
In "Good Cop, Dead Cop" (S01E09), Albuquerque SWAT is seen armed with M4A1 Carbines.
Remington 700PSS
In "Hoosier Daddy" (S01E02), a Mexican Drug Cartel sniper uses a Remington Model 700PSS to try to assassinate a witness. The giveaway is the barrel tip and the bolt handle shape, which both indicate the Remington 700 Action, though one cannot determine the exact caliber (either .308 Win or .300 Win Mag) from a front view (the action length must be visible).