The M31 HEAT is a fin-stabilized anti-tank rifle grenade designed in the late 1950s to replace the Belgian ENERGA rifle grenade which was adopted by the US Army and US Marines as an emergency stop-gap measure during the Korean War.
 Like the ENERGA, it has a nose-initiated, based-detonated HEAT warhead, but unlike the ENERGA, the mechanical impact fuse system is replaced with a less complex and more reliable piezo-electric fuse system which also allows higher angles of impact, up to 65 degrees.
 On impact, the nose cover collapses, crushing a crystal-like material, which sends an electric current through a separate wire to the warhead's detonator, located in the base of the warhead.
 A mechanical safety, comprising a set back system located in the warhead's base, grounds the firing circuit and prevents the accidental explosion of the warhead.
 On firing, the sudden launch acceleration causes the set-back's three disks to rotate 90 degrees, each in succession to the other, with the rotation of the third disk removing the grounding after approximately 10 meters of flight and completing a firing circuit for the current to flow from the nose to the detonator in the base.
 Compared to the ENERGA, the M31 is slightly lighter in weight and has a smaller-diameter warhead—i.e. 75mm vs 66mm.
 Penetration for the M31 is estimated to be "200 mm / 8 inches" for steel armor plating and twice that estimate for concrete.
 The warhead technology developed for the M31 was used for the future M72 LAW antitank rocket.
Troy Industries, Inc. is an American manufacturer of firearms and firearm parts based in West Springfield, Massachusetts.
 It is the manufacturer of parts on the Smith & Wesson M&P15 and is a United States government contractor.
 Troy is best known for its M14 rifle parts and its M7A1 carbine, which was reviewed by the United States armed forces when drafting requirements for a replacement of the M4 carbine.
Maj. Gen. Wilfred Charles Menard, Jr. (November 10, 1918 – February 20, 2012) (ARNG) was the twenty-sixth Adjutant General of New Jersey.
 Commissioned a US Army 2nd lieutenant in 1942, he served actively with the Army during the Second World War rising to the rank of US Army captain.
 He continued to serve thereafter as a reserve officer in the New Jersey Army National Guard, which he commanded from 1974-1982.
 A graduate of the United States Army Field Artillery School, the United States Army Tank Destroyer School, and the United States Army War College, Menard was an experienced artillery officer.
 During his service with the Guard, he was briefly reactivated at the rank of Lieutenant Colonel for the Berlin Crisis of 1961.
 Born in Trenton, NJ, Maj. Gen. Menard was a lifelong resident of central New Jersey.
 His many military awards and decorations include the Distinguished Service Medal (US Army) and the Legion of Merit.
Floyd Lavinius Parks (9 February 1896 – 10 March 1959) was a United States Army general during World War II.
 During the war, he was chief of staff of the US Army Ground Forces and the First Allied Airborne Army.
 As such, he participated in Operation Market Garden that directed air drops into the Netherlands behind the German lines which were preventing Allied forces from crossing the Rhine river.
 He commanded the US First Airborne Army in 1945 on his promotion to major general.
 After the war, Parks commanded the US Sector in Berlin before going to Washington D.C. to become the chief of the Public Information Division for the Army.
 Later, he commanded American forces in the US Army, Pacific in 1949.
 After service in Hawaii, he became chief of the Information Department, whereafter he was known as the "father of modern Army public affairs."
 He received a promotion to lieutenant general in 1953 and thereafter served as Commanding General for the Second United States Army until his retirement in 1956.
The Winchester Hotchkiss was a bolt-action repeating rifle patented by Benjamin B. Hotchkiss in 1876 and produced by the Winchester Repeating Arms Company and Springfield Armory from 1878.
 The Hotchkiss like most early bolt-actions had a single rear locking lug integral with the bolt handle, but was unique in feeding multiple rounds from a tubular buttstock magazine similar to the Spencer rifle.
 The .45-70 Hotchkiss was acquired in limited numbers by the US Navy as the M1879, and (in a slightly modified version) by the US Army and several state militias as the M1883, making it the first center-fire bolt-action repeater to be adopted by any major military (the distinction of first bolt-action repeating rifle to be a issued in great numbers as a standard military arm was the Swiss Vetterli 1869, which utilized very large rim-fire metallic cartridges).
In the US military, a squad leader or squad commander is a Non-Commissioned Officer who leads a squad of typically 9 Soldiers (US Army: squad leader and two fireteams of 4 men each) or 13 Marines (US Marine Corps: squad leader and three fireteams of 4 men each) in a rifle squad, or 3 to 8 men in a crew-served weapons squad.
 In the United States Army the Table of Organization and Equipment (TO&E) rank of a rifle squad leader is Staff Sergeant (US military & naval pay grade E-6 or NATO designation OR-6) and in the United States Marine Corps the TO rank is Sergeant (E-5 or OR-5), though a Corporal may also act as a squad leader in the absence of sufficient numbers of Sergeants.
 Squad leaders of crew-served weapons squads range from Corporal through Staff Sergeant, depending upon the branch of service and type of squad.
The MAS-49 is a French semi-automatic rifle that replaced various bolt action rifles as the French service rifle that was produced from 1949.
 It was designed and manufactured by the government-owned MAS arms factory.
 The French Army formal designation of the MAS-49 is Fusil Semi-automatique de 7,5mm Modele 1949 ("semi-automatic rifle of 7.5mm model 1949").
 The MAS-49 semi-automatic rifle was produced in limited quantities (20,600 units), whereas the shorter and lighter variant, the MAS-49/56, was mass manufactured (275,240 units) and issued to all branches of the French military.
 Overall, the MAS-49 and 49/56 rifles gained the reputation of being accurate, reliable and easy to maintain in adverse environments.
 All the MAS-49 and 49/56 rifles feature a rail on the left side of their receivers to accommodate a designated rifle scope.
 The MAS-49 and MAS-49/56 were replaced as French service rifles by the FAMAS assault rifle in 1979.
The M14 rifle, officially the United States Rifle, 7.62 mm, M14, is an American selective fire automatic rifle that fires 7.62×51mm NATO (.308 in) ammunition.
 It gradually replaced the M1 Garand rifle in U.S. Army service by 1961 and in U.S. Marine Corps service by 1965.
 It was the standard issue infantry rifle for U.S. military personnel in the contiguous United States, Europe, and South Korea from 1959 until the M16 rifle began replacing it in 1964.
 The M14 was used for U.S. Army, Navy and Marine Corps basic and advanced individual training (AIT) from the mid-1960s to the early 1970s.
The Palmer model 1865 carbine is a single-shot bolt action rifle patented in 1863 by E. G. Lamson and Company.
 1000 Palmer carbines were delivered to Union forces in the American Civil War one month after the war ended.
 All rifles (designed to be carbines for cavalry soldiers) were subsequently sold to civilians after the war.
 The rifle was the first bolt action rifle to be accepted for use by the US Army Ordnance Department.
USS "Miantonomah" (ACM-13/MMA-13) was built as the US Army Mine Planter USAMP "Col. Horace F. Spurgin" (MP-14) for the U.S. Army by Marietta Manufacturing Co., Point Pleasant, West Virginia, in 1943.
 "Col. Horace F. Spurgin" was christened by Mrs. Barbee Rothgeb.
 "Col. Horace F. Spurgin" was transferred from the US Army to the US Navy and commissioned as ACM-13 on 25 January 1950.
 After decommissioning and sale to commercial interests 17 February 1961, the ship remained in the fishing fleet into the 1990s before becoming part of a breakwater in Tacoma, Washington.

Question: Troy Industries is best known for the rifle that replaced what model in the US Army by 1961?
Answer: M1 Garand