Avengers: Endgame is the fourth installment in The Avengers film series that began with the 2012 feature. Following the events of Avengers: Infinity War, the 2019 sequel finds the survivors of Thanos' "snap" attempting to find a way to reverse its effects. Anthony and Joe Russo return to direct the sequel, which features many of the cast of Avengers: Infinity War, and would eventually surpass Avatar to become the highest worldwide-grossing feature film of all time. Avengers: Endgame, along with Spider-Man: Far From Home, would mark the end of "Phase 3" of the Marvel Cinematic Universe.
The following weapons were used in the film Avengers: Endgame:
Natasha Romanoff/Black Widow in 2012 is seen holding up one of her Glock 26 pistols during the events of 'The Avengers when present day Tony Stark/Iron Man, Steve Rogers/Captain America , Bruce Banner/Hulk and Scott Lang/Ant-Man arrive.
Glock 26 - 9x19mm Parabellum
On the left, Natasha with the Glock during 2012's Battle of New York, as seen in The Avengers.
Glock 43
Natasha Romanoff/Black Widow (Scarlett Johansson) carries Glock 43 pistols as her sidearms, most notably drawing one of them when confronting the Red Skull (Ross Marquand) on the planet Vormir in 2014. In a deleted scene, she is seen taking target practice with the Glock 26 pistol. She isn't seen with both drawn at the same time in Endgame, save for some BTS footage and photographs which confirm the usage of the Glock 43.
Glock 43 - 9x19mm Parabellum
On the right, Natasha draws her Glock 43 at the Red Skull (Ross Marquand) on Vormir, 2014. The slide is looks rather slim while accompanied by the barrel and also reveals the shaved width profile of the frame and bulging material area where the slide release section is. In the scene where Nat sits realising Red Skull knows her father's name but not her, the Glock 43s slim grips are seen as holstered.
In a deleted scene, Romanoff fires her Glock at a target at the Avengers compound in an alternate scene. The profile appears very slim compared to that of her usual Glock 26.
In a deleted scene, Natasha Romanoff/Black Widow (Scarlett Johansson) is seen taking target practice with what appears to be a Glock 43 pistol. This picture isn't bright enough but other pictures like this shows the shaved width profile of the frame and bulging material area where the slide release section is. The under barrel area of the frame also appears straight and slim like that of a Glock 43 and not wide like a Glock 26.
A BTS image shows Natasha (Scarlett Johansson) dual-wielding her Glocks. The slides,frames and grips here are shown to be very slim
Glock 17
Some S.H.I.E.L.D. Agents in 2012 escorting Loki with Tony Stark and Thor have Glock 17 pistols on their drop leg holsters including present day Tony Stark (Robert Downey Jr.) (which is most likely an airsoft version) while disguised as a S.H.I.E.L.D. Agent of that year. "S.H.I.E.L.D." Hydra Agent Jack Rollins (Callan Mulvey) has a Glock 17 as well while he is in an elevator with Captain America (Chris Evans) in 2012.
Glock 17 - 9x19mm Parabellum
The Glock 17 is seen being carried by S.H.I.E.L.D. Agent Jack Rollins (Callan Mulvey) as he indexes his gun when Captain America (Chris Evans) looks at him behind his back.
Colt M1911A1
A Colt M1911A1 is seen in a holster of a U.S. Army guard at Camp Lehigh in 1970.
Colt M1911A1 - .45 ACP
A Colt M1911A1 is seen in a holster of a guard at Camp Lehigh in 1970.
Rifles/Carbines
M4A1 Carbine
S.H.I.E.L.D. agents carry M4A1 Carbines equipped with EOtech MPO holosights while escorting a restrained Loki (Tom Hiddleston) in 2012.
Colt M4A1 Carbine with M68 Aimpoint reflex sight, Knight's Armament RAS railed handguard and vertical foregrip - 5.56x45mm NATO
S.H.I.E.L.D. agents carry M4A1 Carbines equipped with EOtech MPO holosights while guarding a restrained Loki (Tom Hiddleston) in 2012.
M16A1
US soldiers carry M16A1 rifles at Camp Lehigh in 1970.
Colt M16A1 with 30-round magazine - 5.56x45mm NATO
On the left, US soldiers carry M16A1 rifles at Camp Lehigh in 1970.