The Heckler & Koch HK416 is an assault rifle/carbine designed and manufactured by Heckler & Koch.
 Although its design is in large part based on the AR-15 class of weapons, specifically the Colt M4 carbine family issued to the U.S. military, it uses an HK-proprietary short-stroke gas piston system originally derived from the ArmaLite AR-18 (the same system was also used in Heckler & Koch's earlier G36 family of rifles).
 The HK416 gained fame as the weapon that United States Navy SEALs from DEVGRU Red Squadron used to kill Osama Bin Laden in 2011.
The Heckler & Koch HK41 is a semi-automatic version of the Heckler & Koch G3 battle rifle; it was produced by Heckler & Koch for the civilian market in the 1960s.
 It is not to be confused with the similarly titled Heckler & Koch G41.
The M27 Infantry Automatic Rifle (IAR) is a lightweight, magazine-fed 5.56mm, select-fire weapon based on the Heckler & Koch HK416.
 It is used by the United States Marine Corps and is intended to enhance an automatic rifleman's maneuverability.
 The U.S. Marine Corps is planning to purchase 6,500 M27s to replace a portion of the M249 light machine guns currently employed by automatic riflemen within Infantry and Light Armored Reconnaissance Battalions.
 Approximately 8,000–10,000 M249s will remain in service with the Marine Corps to be used at the discretion of company commanders.
 The United States Army does not plan to purchase the IAR.
Osama bin Laden, the founder and head of the Islamist group Al-Qaeda, was killed in Pakistan on May 2, 2011, shortly after 1:00 am PKT (20:00 UTC, May 1) by United States Navy SEALs of the U.S. Naval Special Warfare Development Group (also known as DEVGRU or SEAL Team Six).
 The operation, code-named Operation Neptune Spear, was carried out in a CIA-led operation, with Joint Special Operations Command, commonly known as JSOC, coordinating the Special Mission Units involved in the raid.
 In addition to SEAL Team Six, participating units under JSOC included the 160th Special Operations Aviation Regiment (Airborne), aka "Night Stalkers," and operators from the CIA's Special Activities Division, which recruits heavily from former JSOC Special Mission Units.
 The operation ended a nearly 10-year search for bin Laden, following his role in the September 11, 2001 attacks on the US.
Operation Tracer was a highly classified World War II military operation based in Gibraltar, a British colony and military base.
 The impetus for the plan was the 1940 scheme by Germany to capture Gibraltar, code-named Operation Felix.
 Operation Tracer was the brainchild of Rear Admiral John Henry Godfrey, the Director of the Naval Intelligence Division of the British Admiralty.
 In 1941, he decided to establish a covert observation post at Gibraltar that would remain operational even if Gibraltar fell to the enemy.
 From the facility, the movements of enemy vessels would be reported back to the United Kingdom.
 Godfrey requested the assistance of several distinguished consultants to bring the plan to fruition.
 The plan was so top secret that Godfrey held meetings with his consultants at his private residence rather than at Whitehall.
 The decision was made to construct the facility using the existing tunnel system for Lord Airey's Shelter, the underground military shelter just north of Lord Airey's Battery.
 The artillery battery was located at the upper ridge of the Rock of Gibraltar, near the southern end of what is now the Upper Rock Nature Reserve.
Operation Maritime Monitor was a NATO operation during the Bosnian War to monitor compliance with sanctions imposed against the former Yugoslavia under United Nations Security Council resolutions 713 (1991) and 757 (1992).
 The operation began on July 16, 1992 and ran until November 22, 1992.
 Under Maritime Monitor, NATO ships from STANAVFORMED and STANAVFORLANT, NATO's standing naval force in the Mediterranean and Atlantic, patrolled in international waters off the coast of Montenegro.
 While NATO forces patrolled off the Montenegrin coast, the Western European Union ran a parallel operation, code-named Operation Sharp Vigilance in the Otranto Strait.
 Maritime Monitor was terminated on November 22, 1992 and replaced by the more aggressive Operation Maritime Guard.
Operation Abirey-Halev or Operation Abirey-lev, also known as Operation Stouthearted Men, code-named Operation Gazelle (Hebrew: מבצע אבירי לב‎ , Arabic: ثغرة الدفرسوار‎ ‎ ), is an Israeli operation that took place in the center of Suez Canal on 15–23 October 1973 during the Yom Kippur War.
Operation Neptune is an educational computer game produced in 1991 by The Learning Company.
 The goal of the game is to guide a small submarine through a variety of undersea caverns, collecting pieces of a ruined space capsule.
 Like other games by The Learning Company, Operation Neptune is educational and was intended for players age nine to fourteen (grades five through nine).
 It was released as part of the Super Solvers series for a time.
Situation Room is a photograph taken by White House photographer Pete Souza in its namesake, the White House Situation Room, at 4:06 pm on May 1, 2011.
 The photograph shows President of the United States Barack Obama along with his national security team, receiving live updates from Operation Neptune Spear, which led to the killing of Osama bin Laden, the leader of al-Qaeda.
Hassan Ghul (Arabic: حسان غول‎ ‎ ), born Mustafa Hajji Muhammad Khan, was a Pakistani or Saudi Arabian member of al-Qaeda who revealed the "kunya" of Osama Bin Laden's messenger, which eventually led to Operation Neptune Spear and the death of Osama Bin Laden.

Question: Who was the Heckler & Koch HK416 used to kill in the operation code-named Operation Neptune Spear?
Answer: Osama bin Laden