Malcolm in the Middle
Malcolm in the Middle is an American television sitcom that followed the misadventures of a dysfunctional lower middle class family and their teenaged son Malcolm, a young savant with an IQ of 160.
Hal Wilkerson, the family patriarch, was Bryan Cranston's most well-known role before being cast as Walter White in Breaking Bad, which won him both critical acclaim and greater stardom. His long-running role as Hal was both an asset and a liability; although it won him widespread notoriety and recognition, the producers of Breaking Bad initially had doubts about casting a comedic actor in such a serious role, but changed their minds after Vince Gilligan, who had worked with Cranston on The X-Files, showed them scenes from Cranston's performance in that show.
As a joke/tribute to what was previously his best-known role, after Breaking Bad concluded, Cranston filmed a short reprise of Malcolm in the Middle with Jane Kaczmarek, in which the events of Breaking Bad turn out to have been an extended dream, that Hal wakes up from.
The following weapons were used in the television series Malcolm in the Middle:
Colt Detective Special
What appears to be a Colt Detective Special is seen used by one of the two criminals robbing Lucky Aid in "Robbery" (S2E07). His Colt is a snub nose with ivory grips.
Colt Single Action Army
Malcolm (Frankie Muniz) finds what appears to be a Walther TPH in an escort's purse in "Poker 2" (S3E13). A nickel plated version is first digitally imposed into the purse using special effects, but later appears in the same episode physically as a Walther PPK missing its safety and sporting a taped grip.
Colt Model 1903 Pocket Hammer
Robber #2 (Maz Jobrani) brandishes the Colt Model 1903 Pocket Hammer with a spur hammer in "Robbery" (S2E07).
Of the two shotguns used in the show, the Remington 870 appears most frequently. Shotguns are commonly used for ranch work and home defense throughout the show.
The Mossberg 500 is the second shotgun seen in Malcolm in the Middle, and is often found in tandem with the Remington 870. The props department most likely only used these two models, as they were reused many times regardless of the show's location.
Reese (Justin Berfield) wields an M4 Carbine rifle with the MILES equipment during his training in "Reese Joins the army Part 2" (S5E22). He also uses the rifle without the training system in "Reese comes home" (S6E01).
Zoo Rifle Cabinet
In "Zoo" (S4E01), numerous firearms, including a dart gun, can be seen behind Lois' ex-lover Matt (Tim DeKay).
Pawn Shop Display Cabinet
A rifle cabinet can be seen in the pawn shop in "Motivational Speaker" (S6e19).
A Police officer deploys a Taser X26 on Hal in "Reese Joins the Army Part 1 (S5E21). The Taser is fitted with a XDPM (Extended Digital Power Magazine) with a spare cartridge.
M2 Hand Grenade
In "The Grandparents" (S02E15), Grandpa Victor (Robert Loggia) gives Reese (Justin Berfield) a surplus Mk 2 hand grenade as a surprise present, but thanks to Reese's stupidity, the pin is pulled and Malcolm (Frankie Muniz) is forced to throw it into the family's brand-new refrigerator, before the three of them flee the house.
N.B. Using a refrigerator to contain the explosion of a grenade is a common trope in several movies and television shows (e.g., Monk), but was tested on an episode of Mythbusters and found to be ineffective.