The Smith & Wesson Model 10, known during the show's era (the 1920s) as the "Military & Police" Model, is the most commonly seen handgun of the show's early seasons. Gangsters including Benjamin "Bugsy" Siegel (Michael Zegen), Chicago mob boss Charlie Sheridan (Frank Shattuck), and Sixtus D'Alessio (Eric Schneider) all carry Model 10 revolvers. Al Capone (Stephen Graham) carries a Model 10 in the front of his waistband until he switches to a M1911 in the first season finale and carries it for the rest of the show's run. In the pilot episode, bootlegger Mickey Doyle (Paul Sparks) carries a S&W Model 10, which Nucky (Steve Buscemi) takes from him. Frankie Yale (Joseph Riccobene) also uses a Model 10 during the climax of the pilot episode. Other gangsters, including Arnold Rothstein's bootleggers in the pilot episode and two of Capone's assassins - likely intended to be John Scalise and Albert Anselmi - in "Marriage and Hunting" (4.09) carry S&W .38 revolvers. In "White Horse Pike" (4.10), Charlie "Lucky" Luciano (Vincent Piazza) draws a S&W .38 when investigating a noise outside the Tampa warehouse. One of Weiss's Chicago gunmen, likely Vincent "Schemer" Drucci, carries a S&W Model 10 during the attempted hit on Johnny Torrio in "Farewell Daddy Blues" (4.12).
On the police side, corrupt Atlantic County Sheriff Elias "Eli" Thompson (Shea Whigham) and his deputies carry holstered Model 10 revolvers. Prohibition agents Eric Sebso (Erik Weiner) and Stan Sawicki (Joseph Aniska) carry them in shoulder holsters, as well. In "Under God's Power She Flourishes" (2.11), lawyer Bill Fallon (David Aaron Baker) confronts Van Alden with Sebso's Model 10. The U.S. Capitol Police detectives who confront Gaston Means in "Havre de Grace" (4.11) carry S&W Model 10 revolvers. The Cuban policemen in "Cuanto" (5.04) carry Model 10 revolvers in their holsters.
The chain gang convict Milton (Warner Miller) takes one from a guard when he and Chalky make their jailbreak in "Golden Days for Boys and Girls" (5.01).
Agent Nelson Van Alden (Michael Shannon) fires a Smith & Wesson Model 10 HB (anachronistic for the 1920s era) at the firing range with the other Prohibition agents in training during the pilot episode.
Smith & Wesson .32 Hand Ejector
"Lucky" Luciano (Vincent Piazza) carries a Smith & Wesson .32 Hand Ejector Third Model, notably seen in "Belle Femme" (1.09) when Gillian Darmody (Gretchen Mol) takes it away from him. Jess Smith (Daniel Cox), the timid and vulnerable assistant to the Attorney General, carries a .32 Hand Ejector in "A Man, a Plan..." (3.10). Some of Gyp's men also appear to carry .32 Hand Ejectors in the third season. As we see in "Marriage and Hunting" (4.09), it also appears to be the preferred sidearm of Chicago North Side crime boss Dean "Dion" O'Banion (Arron Shiver).
Lucky Luciano (Vincent Piazza) has upgraded his .32 S&W Hand Ejector to a .45-caliber Smith & Wesson M1917 by 1921 as seen in "The Age of Reason" (2.06). Vito Scalersio, the assassin sent by Capone to Atlantic City, uses an M1917 in "Peg of Old" (2.07). Gyp Rosetti (Bobby Cannavale) carries an M1917 throughout the third season. Richard Harrow (Jack Huston) also keeps one with his other guns, using it to great effect in "Margate Sands" (3.12). Eli (Shea Whigham) appears to also carry one in a shoulder holster in "Margate Sands" (3.12).
Smith & Wesson Victory Model
Richard Harrow (Jack Huston) uses a Smith & Wesson Victory Model throughout "To the Lost" (2.12), carried in his waistband. It is differentiated from a standard Model 10 by the grips, finish, and lanyard ring. As the Victory Model was developed for World War II, its appearance in an episode set in the summer of 1921 is an anachronism.
Smith & Wesson Second Model Russian
Richard Harrow (Jack Huston) carries a Smith & Wesson Second Model Russian in "Bone for Tuna" (3.03), carried in a shoulder holster under his left arm. This particular revolver is never seen again, so it is unclear if this is one of the many unmentioned weapons in Harrow's arsenal or if it is a continuity error, replacing his more commonly seen break-top Webley.
Webley Mk VI
Richard Harrow (Jack Huston) mentions a "Webley .455" as one of his handguns, finally drawing a Webley Mk VI during a showdown with Sleater in "A Dangerous Maid" (2.03). He also uses it during the whorehouse gunfight in "Margate Sands" (3.12), carried in a shoulder holster under his left arm when not in use.
Colt Official Police
One of Gyp's men "Mexican carries" an anachronistic Colt Official Police in his waistband in "Two Imposters" (3.11). One of Chalky's men appears to carry a similar Official Police in the same scene. This scene is set in May 1923, but the Official Police wasn't introduced until 1927.
Colt Police Positive
Blued
Manny Horvitz (William Forsythe), the Odessa-born Jewish gangster from Philadelphia, carries a blued Colt Police Positive as his main sidearm. One of Nucky's men also carries a blued Police Positive in "Blue Bell Boy" (3.04). Eli (Shea Whigham) digs one out of his garage and hands it to Nucky (Steve Buscemi) in "Sunday Best" (3.07). This is presumably the same revolver that Owen (Charlie Cox) gave Eli in "Spaghetti & Coffee" (3.02). Bureau of Investigation agent Harold Selby (Jacob A. Ware) takes away Eli's Police Positive in "The Old Ship of Zion" (4.08) and hands it to agent Jim Tolliver, aka Warren Knox (Brian Geraghty). Prohibition agent Stan Sawicki (Joseph Aniska) carries a Police Positive - rather than his previous S&W .38 - in "New York Sour" (4.01). Shady businessman Carl Billings (Sean Cullen) takes one from his henchman to threaten Richard Harrow in "Acres of Diamonds" (4.03). Nucky's fourth season assistant and bodyguard Tom (David Campbell) carries a Colt revolver that also appears to be a Police Positive. Chalky White (Michael K. Williams) carries a Police Positive in his waistband when searching for Dr. Narcisse in "King of Norway" (5.05) and "Devil You Know" (5.06).
Nickel
Throughout the third season, Enoch "Nucky" Thompson (Steve Buscemi) carries a nickel Colt Police Positive with pearl grips in a shoulder holster under his left armpit.
Colt New Service
The youngest D'Alessio brother, Pius D'Alessio (Nicholas Martino), desperately attempts to load his Colt New Service in "A Return to Normalcy" (1.12).
Colt Pocket Positive
Nucky Thompson (Steve Buscemi) uses a nickel Colt Pocket Positive in "To the Lost" (2.12), carried in a shoulder holster. The unscrupulous booking agent Dickey Pastor (Jeremy Bobb) holds a snubnose Pocket Positive on Dunn Purnsley in "New York Sour" (4.01). Wisconsin businessman Dolph Liebling (Stephen Paul Johnson) drops his Pocket Positive - also a snubnose model - during a fight with Richard Harrow in "Resignation" (4.02). A corrupt detective from the Chicago PD fires one at Frank Capone in "Erlkönig" (4.05).
Iver Johnson Revolver
Mickey Doyle (Paul Sparks) carries a nickel-plated break-top Iver Johnson revolver in "Bone for Tuna" (3.03). In "Blue Bell Boy" (3.04), the young liquor thief Rowland Smith (Nick Robinson) also carries a nickel Iver Johnson until Nucky's men take it away from him. Harding administration fixer Gaston Means (Stephen Root) carries one when sneaking into Jess Smith's hotel room in "A Man, a Plan..." (3.10). Pinkerton detective Roy Phillips (Ron Livingston) draws a nickel Iver Johnson revolver in "Havre de Grace" (4.11).
Single Action Army
Callum (Joe Tippett), the ignorant Tampa bootlegger working for Bill McCoy, carries what appears to be a blued Single Action Army with white grips in his waistband when meeting Nucky in "The North Star" (4.06).
Smith & Wesson Model 10 Snub
Dr. Valentin Narcisse (Jeffrey Wright) fires what appears to be a nickel Smith & Wesson Model 10 with a 2" barrel in "White Horse Pike" (4.10) after Chalky's gangsters attack his office.
Colt Shooting Master
While working for Al Capone in Chicago, Eli Thompson (Shea Whigham) carries what appears to be a Colt Shooting Master, essentially a target model of the New Service that was introduced in 1933, two years after the scene is set.
Colt Official Police
Introduced in 1927, the Colt Official Police makes its debut appearance in Boardwalk Empire during the show's fifth season, set in 1931 and thus the only season where the Official Police would not be anachronistic. In "Cuanto" (5.04), Sally Wheet (Patricia Arquette) grabs one from a Cuban policeman when she feels her life is being threatened. Nucky's henchman Sean (Nicholas E. Calhoun) carries one, briefly taken away from him by Benny "Bugsy" Siegel (Michael Zegen), in "Friendless Child" (5.07).
Colt Detective Special
The fifth season also marked the first appearance of the Colt Detective Special, which was also introduced in 1927 and thus only appropriate to appear on the fifth season of Boardwalk Empire. Mickey Doyle (Paul Sparks) carries a nickel one with squared pearl grips in the back of his waistband, offering it to Tommy Darmody/Joe Harper (Travis Tope) in "Friendless Child" (5.07) before Nucky (Steve Buscemi) intervenes, taking the Detective Special and handing it back to Mickey.
Unidentified Revolver
In "Golden Days for Boys and Girls" (5.01), Margaret's boss at the financial investment firm, Robert Bennett (Patch Darragh), pulls a nickel revolver from his trouser pocket to commit suicide on the office floor.
Pistols
Colt Model 1903 Pocket Hammerless
Jimmy Darmody (Michael Pitt) carries a Colt Model 1903 Pocket Hammerless in a shoulder holster. It is differentiated from the .380 ACP Model 1908 in "Home" (1.07), when Richard Harrow (Jack Huston) asks Jimmy what type of pistol he is carrying and Jimmy responds: "A Colt 1903". Appropriately, this is also the handgun carried by his son Tommy Darmody (Travis Tope), aka Joe Harper, during the final scene of "Eldorado" (5.08). Richard Harrow (Jack Huston) also has one, seen in his case in "Two Imposters" (3.11).
Nucky (Steve Buscemi) begins carrying his own blued Colt Model 1903 with pearl grips, kept in his inside jacket pocket in the fourth season and then in a shoulder holster for the fifth and final season. Nucky's pistol is best seen in "White Horse Pike" (4.10) and "Farewell Daddy Blues" (4.12).
1911 Pistols
M1911
M1911 pistols are used throughout the series by many characters. Nelson Van Alden (Michael Shannon) carries one in a shoulder holster, both during and after his career as a Prohibition Bureau agent. Al Capone (Stephen Graham) uses one for an assassination in "A Return to Normalcy" (1.12), and the M1911 becomes his standard sidearm through most of the show's run. Some of Sheridan's men in "Family Limitation" (1.06) carry M1911s. Clifford Lathrop (Curt Bouril), the Department of Justice agent assisting Esther Randolph, carries a M1911 in a shoulder holster. Dunn Purnsley (Erik LaRay Harvey), Chalky's second-in-command, also carries a blued M1911 in a shoulder holster. It appears to be the handgun of choice of Gyp's gangsters in the third season, including the ones who attack Nucky in his Ritz Carlton suite in "Two Imposters" (3.11).
After taking control of Atlantic City during the second season, Jimmy Darmody (Michael Pitt) upgrades from a Colt 1903 to a 1911, carried in condition one in a large brown leather shoulder holster.
M1911 (Nickel)
Albert "Chalky" White (Michael K. Williams) carries a matched set of nickel 1911s, notably using them to capture Meyer Lansky in "The Emerald City" (1.10), and carrying them in a double shoulder rig from the first through fourth seasons. Meyer Lansky (Anatol Yusef) uses a chrome M1911 during the standoff in "The Age of Reason" (2.06).
M1911A1
The fourth season finds many characters using the upgraded M1911A1 pistol rather than the previous WWI-era M1911. Richard Harrow (Jack Huston) uses a suppressed model through the early episodes of the fourth season, and his sister Emma (Katherine Waterston) takes it from him to shoot the family dog. It becomes the weapon of choice for most Chicago gangsters in the fourth season, including Al Capone (Stephen Graham) and Frank Capone (Morgan Spector), who hands his off to Nelson Van Alden (Michael Shannon) in "All In" (4.04). After Bureau of Investigation agent Selby takes away Eli's (Shea Whigham) Police Positive in "The Old Ship of Zion" (4.08), Eli begins carrying a 1911A1 in his shoulder holster for the remainder of the fourth season and also uses one during a gangland execution in "Friendless Child" (5.07). Nucky's loyal Cuban bodyguard Arquimedes (Paul Calderon) draws a 1911A1 in "King of Norway" (5.05) when the two come under fire.
Bureau of Investigation agent Jim Tolliver, aka Warren Knox (Brian Geraghty) carries a M1911A1 in a shoulder holster throughout the fourth season as does undercover treasury agent Mike Malone - aka Mike D'Angelo (Louis Cancelmi) - during the fifth season. When Deputy U.S. Marshal Gavin Lynnquist (Hunter Foster) shows up to arrest Chalky in "King of Norway" (5.05), he draws a 1911A1.
M1911A1 pistols are the most frequently seen handguns in the fifth season, a favorite of Al Capone (Stephen Graham) and his henchmen as well as Charlie "Lucky" Luciano (Vincent Piazza) and his cohorts such as "Pinky" Rabinowitz (Ethan Herschenfeld) and Benjamin "Bugsy" Siegel (Michael Zegen). Dr. Narcisse's henchmen also use 1911A1 pistols to gun down a character in "Devil You Know" (5.06).
M1911 Non-Gun
"Bugsy" Siegel (Michael Zegen) files off the serial number of a M1911 "Non-Gun" in "You'd Be Surprised" (3.05). Presumably, a non-gun (or a replica) was used to avoid damaging a real firearm.
Bruni 1911
Wisconsin businessman Dolph Liebling (Stephen Paul Johnson) keeps a 1911 that actually appears to be a second pattern Bruni blank-firing replica in his desk, seen in "Resignation" (4.02).
Remington 1866 Derringer
Eddie Kessler (Anthony Laciura), Nucky's faithful German valet/bodyguard, fires a Remington 1866 Derringer at the D'Alessio brothers when they attempt to kill Nucky in "Belle Femme" (1.09). In "All In" (4.04), Eddie proudly shows Nucky the concealed pistol on his arm, although it's difficult to tell if this is the same derringer he used in "Belle Femme". Sally Wheet (Patricia Arquette) also carries a derringer strapped to her right thigh via garter, but it is taken from her in "Cuanto" (5.04) by a Cuban policeman.
Remington Model 51
Richard Harrow (Jack Huston) uses a Remington Model 51, carried in his right-hand pants pocket, during his assault in "Margate Sands" (3.12).
Savage 1907
One of Masseria's nephews, Incrocci (Mario Macaluso), threatens Jimmy with a Savage 1907 in New York in "Ourselves Alone" (2.02). Richard Harrow (Jack Huston) keeps one in his collection, seen best in "Two Imposters" (3.11).
FN Browning Model 1903
A corrupt detective from the Chicago PD fires an FN Browning Model 1903 at Frank Capone in "Erlkönig" (4.05).
Browning Hi-Power
Although production didn't begin until 1935, four years after the scene is set, Arquimedes (Paul Calderon) appears to draw a Browning Hi-Power rather than a 1911A1 when tensions rise during a stand-off in "Friendless Child" (5.07).
Shotguns
Double Barreled Shotgun
Many characters use full length side-by-side Double Barreled Shotguns throughout the series. Jimmy Darmody (Michael Pitt) uses one when ambushing Rothstein's truck drivers in the pilot episode. Ignacious D'Alessio (Edoardo Ballerini) uses one to rob the casino in "Hold Me In Paradise" (1.08). Many of Chalky's men carry double-barreled shotguns also, specifically when going to war with Gyp's gangsters at the end of the third season. The suspicious bootlegger Elmer rigs one as a booby-trap that surprises Agent Sawicki in "New York Sour" (4.01). Dean O'Banion (Arron Shiver) and his lackey Stu (Joel Marsh Garland) take turns firing a double-barreled shotgun with exposed hammers in "All In" (4.04).
Margaret Schroeder (Kelly Macdonald) uses a double-barreled shotgun that she hands off to Nucky (Steve Buscemi) in "Gimcrack and Bunkum" (2.05); she later carries a similar shotgun in "Ging Gang Goolie" (3.06). Also in "Gimcrack and Bunkum", a hunter named Glenmore (Bill Camp) carries one. Prohibition agents carry double-barreled shotguns during the first season, including Agent Sebso (Erik Weiner) during the raid in "Nights in Ballygran" (1.05). Deputy Halloran (Adam Mucci) carries one in "Anastasia" (1.04). Richard's sister Emma Harrow (Katherine Waterston) also proves to be handy with the family's double-barreled shotgun during the fourth season.
Several flashbacks to 1884 and 1897 in the show's fifth season, most notably in "The Good Listener" (5.02) and "Eldorado" (5.08), show Ethan Thompson (Ian Hart) arming himself with the family's long double-barreled shotgun with exposed hammers.
Browning Auto-5
Browning Auto-5 shotguns are used by several characters throughout the series. In the pilot episode, Al Capone (Stephen Graham) carries a Browning Auto-5, as do several of Rothstein's drivers - including Davey Murdoch (Billy Smith) - and several Prohibition agents. Richard Harrow (Jack Huston) carries a cut-down Auto-5 in the second and third seasons.
Lupara
Luparas are used in several episodes. Al Capone (Stephen Graham) uses one in "Family Limitation" (1.06) to ambush members of Sheridan's Irish mob. Richard Harrow also uses one against the D'Alessio brothers in the episode "Return to Normalcy" (1.12). In "Battle of the Century" (2.09), Waxey Gordon's assassin Alfred Gordetsky (Scott Burik) uses one against Manny Horovitz. Moses, a heroin dealer working with Dunn Purnsley in "The Old Ship of Zion" (4.08), has a lupara holstered under his desk, which Dunn (Erik LaRay Harvey) places next to Moses' body after killing him. Nelson Van Alden (Michael Shannon), working in Chicago as "George Mueller", uses a lupara with exposed hammers to rob one of Al Capone's couriers in "The Good Listener" (5.02).
Winchester Model 1897 Riot
Several of Chalky's employees, including a woman in his warehouse in "21" (2.01) and a man ambushing Dr. Narcisse's office in "White Horse Pike" (4.10), carry Winchester Model 1897 riot shotguns. Chalky (Michael K. Williams) himself gets his hands on a Winchester 1897, taken from his old mentor Oscar Boneau (Louis Gossett Jr.) in "Havre de Grace" (4.11).
Richard Harrow (Jack Huston) uses one when accompanying Jimmy on a revenge mission for the warehouse shooting in "To the Lost" (2.12) and when murdering an opponent in "Resolution" (3.01). Eli Thompson (Shea Whigham) also carries one in "To the Lost" (2.12) and "Margate Sands" (3.12). Many of Gyp's men carry Winchester '97 riot shotguns toward the end of the third season, including one who has his shotgun wrestled away from him by Nucky (Steve Buscemi). Nucky's own gunmen carry them when patrolling his property at the Hotel Albatross in the fourth season and when preparing for a mob war in "Devil You Know" (5.06).
Corrupt Prohibition agents carry them in "Blue Bell Boy" (3.04) when raiding Rowland Smith's warehouse. A corrupt detective from the Chicago PD fires one at Frank Capone in "Erlkönig" (4.05). Agent Tolliver/Knox's Bureau of Investigation agents carry them in "Farewell Daddy Blues" (4.12).
Several Prohibition agents and some of Chalky's warehouse guards carry Winchester Model 1912 riot shotguns. Nucky's gunmen carry them when patrolling his property at the Hotel Albatross in the fourth season. Winston (Brian Tyree Henry), Oscar's nephew, uses a Winchester '12 against some of Narcisse's men in "Havre de Grace" (4.11).
Winchester Model 1912 Full Length
Richard Harrow (Jack Huston) takes a full size Winchester Model 1912 when he goes "hunting" in "Gimcrack and Bunkum" (2.05). A full size Model '12 is also used by a Klansman in "21" (2.01).
Stevens Model 520
A corrupt detective from the Chicago PD fires a Stevens Model 520 pump shotgun at Frank Capone in "Erlkönig" (4.05). Sally Wheet (Patricia Arquette) also has a Stevens shotgun that she sleeps with for safety as seen in "Marriage and Hunting" (4.09). Many of the Maryland prison guards, including the lead guard (Brian Haley), in "Golden Days for Boys and Girls" (5.01) also have Stevens pump shotguns.
Submachine Guns
M1921AC Thompson
Enoch "Nucky" Thompson (Steve Buscemi) travels to Ireland to sell an early shipment of Thompsons to the IRA. The particular model featured is the M1921AC configuration with a 50-round drum magazine of .45 ACP ammunition, not developed until 1926 (anachronistic during a scene set in 1921.) As Nucky himself comments, "No relation." Some of Gyp Rosetti's gangsters in the third season also carry Thompsons. The season is set in 1923, and the Thompson was still not as ubiquitous as it would become later in the decade.
The Thompson is more present in the fourth season, prominently featured when Frank Capone (Morgan Spector) hands one to his brother Al (Stephen Graham) to mow down an enemy in "All In" (4.04). A few episodes later, in "White Horse Pike" (4.10), two of Hymie Weiss's killers fire Thompsons at Capone's office at The Hawthorne Inn in Cicero, a reflection of a real-life event that happened in September 1926. Although much more ubiquitous in the gangland scene by 1931, the fifth season doesn't utilize much of the Thompson submachine gun aside from a scene where Luciano's gunmen ambush Nucky and Maranzano in "King of Norway" (5.05).
Rifles
M1917 Enfield
Richard Harrow uses a scoped Sporterized Enfield M1917 to kill a man in a restaurant, having previously named it in a list of firearms he owns along with a Colt 1903, Roth-Steyr, Smith & Wesson "Triple Lock", and a Mauser 1914. The Enfield rifle proves to be Harrow's preferred weapon, using it to great effect in "Margate Sands" (3.12) and with more tragic consequences in "Farewell Daddy Blues" (4.12).
In "21" (2.01), "Chalky" White (Michael K. Williams) picks one up from a fallen warehouse guard to shoot a KKK member.
M1903 Springfield
During the World War I flashback in "To the Lost" (2.12), Cpl. Jimmy Darmody (Michael Pitt) carries a M1903 Springfield with a bayonet attachment. Some of Chalky's men also carry Springfield rifles, specifically when confronting Gyp in "Two Imposters" (3.11).
One of the three Chicago assassins sent by Hymie Weiss to kill Al Capone in "White Horse Pike" (4.10) fires a Browning Automatic Rifle at the Hawthorne Inn from across the street.
Machine Guns
Browning M1917
A Browning M1917 is used by KKK members to assault a liquor warehouse run by Chalky White in "21" (2.01). In "Margate Sands" (3.12), Capone (Stephen Graham) uses a Browning M1917 to mow down Masseria's killers.
Other
Mark I Trench Knife
Jimmy Darmody (Michael Pitt) carries a 1918 Mark I Trench Knife in his left boot. The writers are doing a little bit of homework on this series as when Jimmy is asked what the point on the top of the handle is he says it's a skull crusher and is used for "cracking walnuts."
Colt Percussion cap gun
Eli Thompson (Shia Whigham) works to fix a cap gun resembling a Colt percussion revolver for his son Brian in "Gimcrack and Bunkum" (2.05).