A Beretta 92FS is the handgun used throughout Season 3.
Beretta 92FS Inox
What appears to be a Beretta 92FS Inox is seen in Carrie's safe in "Yoga Play" (S3E05).
CZ-75B
Iranian security forces appear to pull CZ-75B pistols on Brody and Carrie in Season 3's finale "The Star" (S3E12).
Kimar Model 92
In Season 3's finale "The Star" (S3E12), Brody takes what appears to be a Beretta 92FS Inox out of a desk drawer and pulls it at a checkpoint. The pistol appears to be a Kimar Model 92 replica pistol.
SIG-Sauer P226 E2
CIA operative Peter Quinn (Rupert Friend) uses a SIG-Sauer P226 E2 fitted with a suppressor in Season 3's premiere "Tin Man is Down" (S3E01).
Rifles
M4A1
The Colt M4A1 is seen in the hands of SWAT agents in the series.
AKM
AKM rifles are held by various guards and insurgent forces.
Zastava M70
What appears to be a Zastava M70 is seen in the hands of one of the CIA operatives when in Iraqi Kurdistan in "Good Night" (S3E10).