Travis Bickle (Robert De Niro) purchases four handguns from "Easy Andy" (Steven Prince), the illegal gun salesman. The first of which is a Smith & Wesson Model 29 with an 8 3/8" barrel, the longest factory barrel made for the S&W Model 29 during this time period. The other two stock barrel lengths at the time were the 4" barrel and the 6.5" barrel. Travis apparently gets the idea of owning a .44 Magnum from one of his passengers (played by director Martin Scorsese) who claims he will use it to murder his cheating wife. Travis's Model 29 is seen often throughout the film, carried in a large shoulder holster he purchased from "Easy Andy" for $40, in addition to paying $350 for the revolver itself.
Travis Bickle (Robert De Niro) also purchases a nickel Smith & Wesson Model 36 with a square butt, mother-of-pearl grips, and a flared flat cylinder release hatch (dating it from the late 50s to early 60s) after "Easy Andy" suggests it as a more practical weapon. Travis purchases it from him for $250. A mobster in the whorehouse during the final shootout has a blued Model 36, which Travis takes from him and uses. In a continuity error, the Smith & Wesson Model 36 becomes a nickel Colt Detective Special when Travis fires it at the range (see below).
Travis Bickle (Robert De Niro) also buys a Smith & Wesson Escort from "Easy Andy", who incorrectly refers to it as a "Colt .25" and sells it to him for $125. Travis attaches the Smith & Wesson Escort to a drawer slide, mounting it on his forearm and later using it during the final shootout. In a continuity error, this is seen as a Sterling Arms pistol when Travis is firing it at the range.
Travis Bickle (Robert De Niro) buys an Astra Constable for $150 from "Easy Andy", who not only mistakenly refers to it as a ".380 Walther", but also claims that "during World War II, they used this gun to replace the Walther P38 pistol. Just gave it out to officers" and claims it can hold eight rounds in the "clip" (meaning magazine). This is the only handgun Travis buys that he doesn't keep in any sort of holster, choosing instead to tuck it in the waistband of the small of his back. He hands it to the grocery store owner (Victor Argo) after killing the robber with it. In a continuity error, this is seen as a Walther PPK (most likely the actual weapon Andy was referring to) when Travis is firing it at the range. Easy Andy says it has 6+1 capacity, and claims that it is dumb to carry a round in the chamber. This is a potential goof because most people carry their guns chambered and with the +1.
Iris's pimp Matthew, a.k.a. "Sport" (Harvey Keitel) fires a nickel Smith & Wesson Model 10 at Travis. Some NYPD officers also carry standard Model 10s.