Point of No Return, an Americanised remake of La Femme Nikita, has Bridgitte Fonda (I think) asassinate a guy in a restuarant with what looks like a Hammerli Olympic match pistol. Interestingly, although the gun is .22LR, the report is overdubbed with some sort of centerfire blast. A lot of goods guns in that movie, including when the girl pulls a stainless syntho-stocked bi-podded bolt-gun out from under the bubbles in her bathtub. I can't think of another movie where a competition-style handgun is used, and the Hammerli got dragged through the dirt by being small enough to conceal, and then shooting somebody at point-blank range.
Not a Walker Colt, but impressive all the same, was the 1851 Navy used with it's detachable shoulder stock by the lead character in The Bushido Blade. It was notable enough to have one of the Japanese character's comment on it's sophistication compared to the matchlocks that his country had. This is the only use of a detachable shoulder stock I know of.
Whoopi Goldberg winds up in a creep-around gunfight in a department store in Jumping Jack Flash. When she runs out of ammo for her snubby revolver, she winds up in Sporting Goods to smash the glass on a case to get a Winchester levergun and a new box of ammo.
I can't think of titles, but I do remember a high-level foreign-ese intelligence agent of Russian or German extraction being incongrously armed with a Spanish Astra 400, and a rather flamboyant American mob-enforcer-type dude who walked around with a .45-70 T/C Contender that he was always doing a one-handed open/ejection-yank maneuver with. He had to be using virgin brass, though, as the cases were easily flipped out, with accompanying loud jingle on the ground while his off hand dug in a pocket for a fresh round. (I say flamboyant because this guy not only used a 14"-barreled, over-powered single-shot pistol, he left empty cases all over the landscape. Not the work of a professional, but it sure looked cool.) Hmmm. On reflection, both of these may have been TV shows, rather than movies.
I'd like to see more use of single shot rifles of all sorts. Quigley had his Sharps, of course, and Val Kilmer used Martini-Henry's in The Ghost and The Darkness alongside Micheal Douglas' double rifle, but single-shots have a tendency to be under-represented. (Exception: cavalry in cowboys-'n-injun flicks usually have Trapdoor carbines, and the British troops in Zulu had Martini-Henry's too.)
'Nuther good gun for movies would be Merwin & Hulbert revolvers with their twist-and-pull ejection system. Never seen 'em anywhere. And we always talk about Stechkins and Skorpions, but I can't recall a seeing any on film.
I DO remember seeing a Makarov on TV once, but it wasn't in a movie, it was in a holster on Boris Yeltsin's hip.