John Dillinger (Johnny Depp) carries two Colt M1911A1 pistols kept in a leatehr cross-draw shoulder holster rig throughout the film, rarely firing them. Several other of his gang members also carry and use them, including Harry "Pete" Pierpont, Homer Van Meter (Stephen Dorff), Walter Dietrich (James Russo), Charley Makley, and "Baby Face" Nelson (Stephen Graham). Charles "Pretty Boy" Floyd (Channing Tatum) reaches for a nickel 1911 when he is shot down in an Ohio field, but Purvis kicks it from his hand. The pistols used by the prison escapees (most of Dillinger's gang) in the opening scene are 1911s smuggled into the prison by Dillinger. FBI agents such as Melvin Purvis (Christian Bale) and Charles Winstead (Stephen Lang) also fire 1911s, during the Little Bohemia and Biograph Theater scenes respectively. While Dillinger was said to prefer .38 Super pistols in real life, there are currently no .38 Super weapons or blanks in the armorer industry, and all of the M1911A1s in the film were chambered in .45 ACP.
Colt Thompson Hybrids
John Dillinger (Johnny Depp) and several other of his gang members, notably "Baby Face" Nelson (Stephen Graham), Harry "Pete" Pierpont, and John "Red" Hamilton (Jason Clarke) have Thompsons, sometimes seen with the stock removed with a lanyard attached. Charles "Pretty Boy" Floyd (Channing Tatum) carries a fires one as he is being pursued by Purvis. During the breakout from Crown Point jail, Dillinger hands a Thompson to Herbert Youngblood (Michael Bentt). FBI agent Melvin Purvis (Christian Bale) also uses a Thompson in several scenes. During the Little Bohemia shootout, there was a continuity error with Purvis' Thompson. He started out with a drum magazine, but then when he was empty and reloaded, it instantly switched to a stick magazine.
The guns used in the film were a mix of Colt M1921s (Some the same used in Indiana Jones and the Kingdom of the Crystal Skull) with 1928 internals, M1928A1s refinished to look like M1921s (by adding a polished blued finish) and there were some Thompson hybrids that were built out of various models. (thanks goes to Steve Karnes for the information on the guns)
Remington Model 11
John "Red" Hamilton (Jason Clarke) uses a sawed-off Remington Model 11 as his primary weapon during the film's early scenes, such as the Indiana State Prison break and the Racine bank robbery. The lead Tucson policeman arresting Dillinger and several FBI agents also have Remington Model 11 shotguns, mostly with sawed-down stocks and barrels.
Winchester Model 1892
Winchester Model 1892 rifles are used by prison guards at the Michigan City prison. One is also used by a vigilante to graze Dillinger in the shoulder during the Sioux Falls bank robbery botched by "Baby Face" Nelson.
M1903 Springfield
Some of the Indiana State Prison guards at Michigan City carry M1903 Springfield rifles, as do soldiers guarding the streets outside Crown Point jail several months later. These are not, as previously suggested, 1940s-era M1903A3s, but the correct M1903, identified by it's humped upper handguard. John "Red" Hamilton (Jason Clarke) aims a Springfield at the mobster at the farmhouse after Dillinger's prison break. A vigilante in Sioux Falls is also briefly seen with one.
Mauser 98 Sporter
Melvin Purvis fires a half-stocked Mauser 98 Sporter when searching for "Pretty Boy" Floyd (Channing Tatum) in Ohio. He ultimately uses it to fatally wound Floyd after taking a well aimed shot at him as he flees, making use of the double set triggers to lighten the trigger pull and make his shot more accurate. This is a German-style purpose-built sporter with a ribbed barrel, express sights and a flat "butterknife" style bolt handle, and not a converted military rifle. It is not, as some have suggested, a Mannlicher-Schonauer, though they were quite popular among sportsman of the era.
Winchester Model 1897
Many lawmen use the Winchester Model 1897 pump shotgun throughout the film, including the two FBI agents escorting Purvis as he chases Floyd through Ohio. Many of Dillinger's guards upon his arrival in Crown Point also have Riot and full-barreled versions.
Tommy Carroll (Spencer Garrett) uses a Winchester '97 during the Sioux Falls bank robbery.
U.S. Krag 1898
The uniformed Ohio police officers aiding in Purvis's pursuit of "Pretty Boy" Floyd carry US Krag rifles, most likely M1898s. Similarly, a plainclothes guard is seen carrying an M1898 Krag carbine when Dillinger leaves his interview at the jail.
Colt Detective Special
Several FBI agents are seen with Colt Detective Specials, usually seen in their hip holsters. Melvin Purvis (Christian Bale) is notably seen with one holstered in several scenes.
Colt Model 1903 Pocket Hammer
John "Red" Hamilton (Jason Clarke) has a Colt Model 1903 Pocket Hammer tucked into his waistband as he enters the whorehouse after assisting in the the Indiana State Prison escape.
Browning Automatic Rifle
One of Dillinger's bank robbers, Homer Van Meter (Stephen Dorff), uses a Browning Automatic Rifle during several of the gang's robberies. One of Purvis' FBI men is also seen firing a BAR during the Little Bohemia shootout. Van Meter's BAR has a notably shorter barrel than the standard models released, although it was actually Bonnie & Clyde who favored the sawed down BARs, and not Dillinger's gang. The weapons were modified in the "Bonnie & Clyde" configuration and supplied by Gibbons Ltd. for the film. In a documentary about the film, Dorff joked that handling the weapon one-handed often felt like it weighed seventy five pounds.
Smith & Wesson Model 10
When Purvis tells FBI agent Barton to wait in the alley when going to arrest Nelson in the apartment building, Barton draws a Smith & Wesson Model 10 that he later uses to fruitlessly trade shots with the Thompson-armed Nelson. Several other FBI agents are seen with Model 10s.
Colt Model 1903 Pocket Hammerless
John Dillinger (Johnny Depp) keeps a Colt Model 1903 Pocket Hammerless as a secondary sidearm, most notably as a "pocket pistol" when in hiding in Chicago after the Little Bohemia shootout. It is also seen when he places it down on a hotel room table in Tucson, earlier in the film.
Smith & Wesson Military & Police
The Tucson policeman who removes Dillinger's handcuffs after he is arrested in the hotel has a very early production Smith & Wesson Military & Police revolver in his holster. It has the rounded hard rubber grips only used between 1899-1905.
Remington Model 8
John Dillinger (Johnny Depp) grabs a Remington Model 8 autoloading rifle during his breakout from Crown Point jail. These rifles are also seen in the hands of several FBI agents and policemen.
unidentified rifle
Court officers in Crown Point carry rifles during Dillinger's arraignment.
Colt Official Police
John Dillinger (Johnny Depp) takes a Colt Official Police when he breaks out of Crown Point, tucking it in his waist. The FBI agent who beats Billie Frechette, Harold Reineke, also carries an Official Police when attempting to arrest Dillinger. He draws it too early, allerting Dillinger and preventing his being taken alive.
Colt Model 1922 Machine Gun
Army soldiers guarding the streets during Dillinger's Crown Point jail escape are seen manning a Colt Model 1922 Machine Gun.
Winchester Model 1912
Winchester Model 1912s are seen used throughout the film by FBI agents, local police, and the Mafia guards at the syndicate booking parlour.
Winchester Model 1907
After Dillinger breaks out of Crown Point, a customized Winchester Model 1907 with a ten-round magazine and a Thompson foregrip enters the gang's armory, with Homer Van Meter (Stephen Dorff) using one during the Sioux Falls robbery and Ed Shouse (Michael Vieau) firing it during the Little Bohemia gunfight. This is historically accurate since this weapon was found among the weaponry in Dillinger's crew, seen in the photo linked from this article. Earlier in the film, Purvis also tells his agents that they will receive, in addition to Thompsons and B.A.R.s, .351 Winchester semi-automatic rifles, most likely referring to the Model 1907.
Colt New Service
A Colt New Service revolver with a 5 1/2" barrel is seen in a man's hand before Nelson opens fire on him in Sioux Falls.
Winchester Model 1901
FBI agent Charles Winstead (Stephen Lang) fires a sawed-off Winchester Model 1901 chambered in 10-Gauge during the Little Bohemia shootout.
Dillinger's Colt .38 Super "Machine Pistol"
John Dillinger carried a rather unique firearm at one point, an Colt .38 Super chambered in .38 Super (which would pierce body armor when the .45 ACP round wouldn't) which was specially modified to fire full auto, loaded with an extended magazine, was fitted with a Thompson's foregrip and a Thompson's Cutts compensator to turn it into a miniaturized "machine pistol". In the film Dillinger is sadly never seen using it, and it is only wielded in the hands of "Baby Face" Nelson (Stephen Graham), who uses it during the Little Bohemia shootout to fire out the windows and later to gun down an FBI agent before stealing his vehicle.
Winchester Model 1897 Trench
When Billie Frechette (Marion Cotillard) is apprehended by the FBI, one of the agents is seen carrying Winchester Model 1897 "Trench" model with a heat shield and a bayonet lug.
"Wooden Gun"
John Dillinger (Johnny Depp) crafts himself a "Wooden Gun" that he uses to break out of Crown Point jail before several guards realize it was fake.
Special
This is a collection of firearms that where captured from the real Dillinger gang. As you can see the makers of the movie put a lot of these weapons into the movie. Included with the weapons is Dillinger's death mask and the hat he wore when he was killed. Above the hat is the clothes he was wearing when he died including his sunglasses and the cigar he had.