In Season 5's premiere, "Company Man", CIA officer Max (Grant Show) carries one as his sidearm.
SIG-Sauer P226
A SIG-Sauer P226 appears to be the weapon used to frame Michael for a murder. In "Army of One" (S5E10), a SIG-Sauer P226 is taken off a hostage taker by Michael that he later gives to his mother Madeline to use.
Agent Dani Pierce (Lauren Stamile) also carries a SIG-Sauer P226 as her sidearm.
SIG-Sauer GSR
What appears to be a nickel-plated SIG-Sauer GSR is held by Dion Carver (Andre Holland) in "Breaking Point" (S5E14).
American Tactical Imports FS9 (TiSAS Zigana Sport)
In "Necessary Evil" (S5E15), the Liberian warlord Joseph Kamba (Jonathan Adams) uses an ATI FS9 Sport, the US import version of the TiSAS Zigana Sport.
Beretta 92FS
Sam Axe (Bruce Campbell) carries a Beretta 92FS as his personal sidearm throughout the series. The Beretta has also seen use by various other characters throughout the series' run, in both suppressed and unsuppressed forms.
Colt M1911 Series
Colt 1911 series handguns are seen numerous times throughout the series.
Glock 17
In "Mind Games" (S5E03), Fiona is seen putting a "standard police-issue" Glock 17 in a box in order to frame a loan shark as being an undercover cop.
Glock 26
In "No Good Deed" (S5E04), Eve (Aviva Farber) carries a Glock 26 as her sidearm.
Mossberg 500 Persuader (Folding Stock and Door Breaching Brake)
A frequent shotgun seen used in the series is a Mossberg 500 Persuader fitted with a police folding stock, saddle shell holder, and door breaching brake.
USAS-12
In "Breaking Point" (S5E14), Michael is seen showing off a variety of weapons to gangster Dion Carver, which includes a USAS-12.
Assault Rifles
Heckler & Koch HK91
The Heckler & Koch HK91 is used in several of Season 5's episodes. Michael takes one off a guard in "Enemy of My Enemy" (S5E06). It's also seen in the hands of a militia leader in "Besieged" (S5E07). The rifle is specifically identified by name as the weapon used in the murder of a war criminal in "Army of One" (S5E10).
In "Besieged" (S3E07), both Fiona and Sam are seen carrying the G36C.
M4A1 Carbine
In "Army of One", Sam provides cover for Michael with an M4A1 that is fitted with an Ace stock. In Season 5's "Better Halves", Michael fends off some assassins with an M4A1 fitted with a EOTech sight and mags taped together "jungle" style.
SIG SG 552
A completely black SIG SG 552 assault rifle is used by Fiona in Enemy of My Enemy" (S5E06). A SIG SG552-2 fitted with an EOTech sight is held by Fiona in Season 5's "Damned If You Do..." (S5E13).
Sniper Rifles
Barrett Model 98 Bravo
In Season 5's "Square One" (S5E05), former Special Forces sniper Ethan (Matt Lauria) is seen using a Barrett Model 98 Bravo sniper rifle to take aim at the man who put his sister in the hospital.
Grendel SRT
In Season 5's "Dead to Rights", Fiona uses a Grendel SRT rifle to fire two rounds into a window of the British consulate. In Season 5's "Depth Perception" (S5E16), Fiona provides cover with the Grendel.
Sako TRG-42
In Season 5's "Depth Perception", an outed Russian spy is seen using a Sako TRG-42 rifle throughout the episode to try and eliminate Sam and Beatriz.
Mk 12 Special Purpose Rifle
Fiona uses a black suppressed Mk12 SPR to cover Michael's impromptu meeting with Anson in Season 5's "Fail Safe."
Winchester Model 70
A Winchester Model 70 is frequently used by Sam to cover Mike or to provide distractions.
Heavy Weapons
RPG-7
In "Breaking Point" (S5E14), Michael is seen showing off a variety of weapons to gangster Dion Carver, which includes an RPG-7. Carver is later seen using the RPG on a truck.
Other
M67 Hand Grenade
In Season 5's "Army of One", Holcomb also threatens the hostages with an M67 hand grenade. He later gives the grenade for Michael to use.
Zip Gun
In Season 5's "Army of One", Michael assembles an improvised Zip Gun that he uses to wound a hostage taker.
Simunition
In Season 5's "Acceptable Loss", Michael is seen loading Simunition training rounds into a Beretta.
Molotov Cocktail
Michael tosses a Molotov Cocktail into a con artist's sports car in Season 5's "Square One"