Throughout the six films of the Star Wars saga, creator George Lucas was determined that the universe he envisioned would have a "lived-in" look to it. Thus, the many weapons seen in the saga are in fact visually modified or based upon real-world weapons. Note: This page encompasses all six films of the Star Wars saga.
The following lists the real-world firearms that were visually modified for use in the six films of the Star Wars saga:
Original Trilogy (Episodes IV, V, and VI)
Vostok Margolin .22LR target pistol
In the early scenes of A New Hope and in a few scenes in Return of the Jedi, Princess Leia (Carrie Fisher) can be seen with a Defender Sporting Blaster, actually a Vostok Margolin .22LR target pistol, with some muzzle attachment fitted. Among other details, the Return of the Jedi version lacks the commercially available compensator that the A New Hope prop had.
BlasTech E-11 blaster rifle (Sterling L2A3)
Standard issue blaster rifle of the Imperial Stormtroopers. The E-11 blaster rifle props were built from the British-made Sterling L2A3 submachine gun. Numerous main characters, including Princess Leia, Luke Skywalker (Mark Hamill), and Han Solo (Harrison Ford) use the weapon. Lando Calrissian (Billy Dee Williams) also uses an E-11 blaster in The Empire Strikes Back. Some details differ between the three movies, most notably the method of scope attachment and battery pack beside it (or lack thereof).
A revealing mistake is that spent cartridge cases can be seen ejecting from this "blaster" rifle. It is most noticeable in the bridge swing scene of A New Hope and Lando firing at Stormtroopers in The Empire Strikes Back. Rather strangely, Return of the Jedi made no use of blanks with this weapon.
BlasTech DH-17 Blaster Pistol
First seen in A New Hope used by Rebel troops against Stormtroopers on the blockade runner Tantive IV. Later seen carried by guards and officers on the Death Star. These were nonfunctional props with the receiver and pistol grip based on casts from a Sterling SMG. Consequently, the muzzle flashes in the first scene were added in post-production. There is an interesting continuity error where a couple of guards start off carrying this weapon but then switch to the E-11, firing it one handed like a pistol no less. This is perhaps because they looked similar enough and blanks provided a better reference point for adding blaster effects later.
In The Empire Strike Back, it is the weapon of a few Rebel soldiers on Hoth and a couple of guards on Darth Vader's Super Star Destroyer. This time around, they were built from an actual Sterling SMG rather than a cast and have a more realistic scope attached. It is then curious why none of the props are seen firing blanks and the weapon has far less screen time than in the previous film.
BlasTech A280 and A295 blaster rifles
Standard issue blaster rifle of the Rebel Alliance ground forces in both The Empire Strikes Back and Return of the Jedi. Both the A280 and A295 blaster rifle props were CAST FROM replicas similar to (built from) both the World War 2-era German Sturmgewehr 44 (A295 - The Empire Strikes Back) and from the M16 series rifles (A280 - Return of the Jedi).
DLT-19 heavy blaster rifle (MG34)
Standard issue heavy blaster of the Imperial Stormtroopers. The DLT-19s were nothing more than World War II German MG34 general purpose machine guns with little to no modifications to its external appearance.
T-21 Light Repeating Blaster (Lewis Machine Gun)
The heavy blaster seen carried by the Sandtrooper Officer is a modified British Lewis light machine gun.
RT-97C heavy blaster rifle (MG15 machine gun)
Imperial Sandtroopers can be seen carrying RT-97C heavy blaster rifles while on patrol on Tatooine. The RT-97C heavy blaster rifle prop is in fact a modified German MG15 machine gun.
BlasTech DL-44 blaster pistol (Mauser C96)
The DL-44 blaster pistol was the blaster of choice for Han Solo (Harrison Ford) and the Rebel Alliance. The weapon is seen wielded by Luke Skywalker (Mark Hamill) throughout The Empire Strikes Back. Possibly the best known duplicate of a real gun, the DL-44 blaster pistol prop was built from a Mauser C96 handgun, sometimes with a sniper scope. The modifications are obviously added on to the exterior, though the distinct "broomhandle" grips are still wooden.
Jawa Ion Blaster
The Ion blaster utilized by the Jawa who shot R2-D2 in A New Hope was built from a cut-down British Lee-Enfield No.1 MkIII* series bolt-action rifle with the grenade launcher cup attached to the shortened barrel.
Boba Fett's EE-3 Blaster Carbine
The prop Boba Fett uses in the films is a modified Webley & Scott No.1 Mark 1 Flare Gun. In The Empire Strikes Back the barrel was rather simple looking. In Return of the Jedi it has a more distinctive barrel and the scope is actually mounted backwards to where it was before!
Ponda Baba's SE-14C blaster pistol
The SE-14C blaster pistol is carried by Dr. Evazan and, with scope removed, his crime partner Ponda Baba in A New Hope. They draw these weapons after provoking a fight with Luke Skywalker at the Mos Eisley cantina. It was built from a Swiss Rexim-Favor Mk5 submachine gun with the stock, barrel, and magazine removed and has a double sniper scope attached.
Orrimaarko's (Prune Face) Dressellian projectile rifle (Mauser Kar98k)
An unmodified Mauser Kar98k bolt-action rifle was seen in the hands of the character Orrimaarko a.k.a. "Prune Face" in promotional photos for Return Of The Jedi.
Prequel Trilogy (Episodes I, II, and III)
S-5 Blaster Pistol
In Episode I The Phantom Menace, the Naboo troops used this weapon that was based around a Walther LP300 Model Air Gun.
Also seen in The Phantom Menace is the Naboo CR-2 Blaster, which appears to be based off of the Calico M950A.
DC-15A Heavy Plasma Rifle
Manufactured by BlasTech Industries, the DC-15-series was a range of plasma weapons used by the Republic clone troopers during the Clone Wars in Episode II Attack of the Clones and Episode III Revenge of the Sith. Although entirely computer-generated (as are all the Clone Troopers, no costumes were manufactured,) its design is based on parts from the German MG34 making up the rear half, as well as much of the Sterling L2A3 turned upside-down for the front.
DC-15S Compact Plasma Rifle
Like the M16 has the M4, the DC-15A has the DC-15S. It is basically a compacted version (a "carbine" if you will) of the DC-15, lacking some of the range but making up for it in ease of use and portability. It is usually seen in the hands of officers, most notably Commander Bacara when he and the Galactic Marines kill Ki-Adi-Mundi, as well as in the hands of many regular clone troopers (the design of the DC-15S carbine would later influence the design and development of the E-11 blaster rifle used by the Imperial Stormtroopers in Episodes IV-VI). As this weapon is computer generated, what it is based upon (if any) is currently unknown; its similarity to the E-11 suggests it was based on the Sterling L2A3 as well.