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 (portrayed by director Martin Scorsese in a cameo) 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 leather 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 five-shot nickel Smith & Wesson Model 36 first pattern model with a square butt, mother-of-pearl grips, a slightly cut down hammer, and a flared flat cylinder release hatch (dating it from the late 50s to early 60s) rather than the later rounded latch. Bickle buys it 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 Model 36 becomes a nickel Colt Detective Special when Travis puts it down in front of him at the range (see below).
A gunman (Nat Grant) attempts to rob a grocery store with a nickel-plated Smith & Wesson Model 10 revolver, but is stopped by Travis. Iris's pimp Matthew, a.k.a. "Sport" (Harvey Keitel) also fires a nickel Smith & Wesson Model 10 at Travis. It is possible that these are the same gun.
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. Easy Andy apparently confused the S&W Escort with the similar-looking Colt 1908 Vest Pocket in .25 ACP. 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 puts it down 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 putting it down at the range.
When Travis Bickle (Robert De Niro) switches his handguns at the shooting range his S&W Escort becomes a Galesi-Brescia Brevetto 5 ("Brevetto" is Italian for "Patent", meaning this particular model is the Patented Model 5, the Model 9 has a longer barrel). This particular Galesi-Brescia model coming with stainless finish and faux ivory grips (noted by the AG medallion), either in .22 LR, .25 ACP or .32 ACP.
