Castle - Season 4
The following weapons were used in Season 4 of the television series Castle:
Smith & Wesson SW1911
A stainless steel Smith & Wesson SW1911 can be seen in "Cops and Robbers" (S4E07).
Smith & Wesson Model 60
A suspect pulls a Smith & Wesson Model 60 in Season 4's premiere "Rise" (S4E01).
Smith & Wesson Model 15
A Smith & Wesson Model 15 is drawn by an officer in "Cops and Robbers" (S4E07).
Heckler & Koch MP5K
Some of the bank robbers are armed with the Heckler & Koch MP5K (fitted with PDW stocks) in "Cops and Robbers" (S4E07).
Esposito (Jon Huertas), as well as most NYPD ESU officers use M4A1s when needed, notably in "Cops and Robbers" (S4E07).
Knight's Armament SR-25
A Knight's Armament SR-25 can be seen in Season 4's premiere "Rise" (S4E01). It is recovered after the attempted assassination attempt on Beckett, as seen in Season 3's finale "Knockout" (S3E24). Esposito refers to it as a Mk 11, which is correct as this particular rifle was a Navy SEAL issue weapon. In "Kill Shot" (S4E09), Beckett and Esposito are seen handling the rifle.
Remington 700 AICS
A Remington Model 700 AICS fitted with a suppressor and a Harris bipod is seen in "Kill Shot" (S4E09). The rifle is loaded with 165 grain .308 Winchester ammo.