Rifles That Shaped Rifles: Assault Rifle Lineages from the AR-18 to the INSAS

Begin with a rifle that was a commercial and design footnote. Arthur Miller designed it in 1963 with input from Eugene Stoner at ArmaLite as a cheaper alternative to the AR-15 after the United States military chose that earlier design as the M16. Only 1,171 AR-18s and 21,478 of the semi-automatic AR-180 were made between 1969 and 1985, yet it reached irregular forces from Malaya to Northern Ireland and its gas piston design influenced later rifles.

Here is the design the AR-18 was meant to undercut. Colt bought the 1956 ArmaLite AR-15 design and trademark in 1959, sold fully automatic versions to the Federation of Malaya and the United Kingdom, and introduced the semi-automatic civilian Sporter in 1964. Colt has built more than two million rifles under the name.

Shortening the same rifle produced a family of its own. Colt marketed the CAR-15 in the 1960s and early 1970s, best known as the Colt Commando or XM177, a select-fire carbine with a barrel of 10.5 or 11.5 inches. Colt introduced it in 1966 in response to the American military wish for a shorter M16, and the family served from 1966 into the 1990s.

The AR-15 layout then met the piston. The HK416 is built on the AR-15 and M16 platform but replaces direct impingement with a short stroke gas piston derived from the G36 family. It entered service in 2004, won attention when United States Army Delta Force adopted it, and the Marine Corps later fielded a variant as the M27 Infantry Automatic Rifle.

Now to the other great lineage. Mikhail Kalashnikov's AKM was introduced in 1959 as a lighter, more easily manufactured successor to the AK-47, built at Izhmash and Tula and later under license elsewhere. With production estimated above ten million, it became the most widely produced variant of the whole Kalashnikov family.

A licensed copy shows how the design traveled. China began adopting the Type 56 in 1956 after the Soviet Union supplied information and production equipment for the AK in 1955. The earliest rifles were milled-receiver copies of the AK-47, later production moved to stamped receivers like the AKM, and more than ten million have been built. A fully enclosed hooded front sight sets it apart.

Israel adapted the Kalashnikov rather than copying it outright. Yisrael Galili and Yakov Lior drew heavily on the Finnish RK 62, itself derived from the AK-47, and Israel Military Industries began production in 1972. The Army fielded three configurations, the ARM, the AR and the SAR, and a modernized Galil ACE has been made since 2008.

Not every Russian rifle followed the AK pattern. Designer Stanislav Koksharov developed the AEK-971 at the Kovrov Mechanical Plant in 1978 around a balanced automatic recoil system meant to keep the weapon steady in automatic fire. It has been in service since 1980 and has armed Russian military and Spetsnaz units in the Second Chechen War and the 2022 invasion of Ukraine.

Germany took a different road with a short stroke gas piston and a closed rotating bolt. Designed between 1991 and 1995, the G36 was accepted by the Bundeswehr in 1997 and adopted by more than 40 countries. Germany has announced plans to replace it with the HK416, designated G95A1, closing a loop with the fourth stop on this path.

Bullpup layouts put the action behind the trigger. The Tavor, first fielded as the TAR-21, was designed through the 1990s and early 2000s around a long stroke gas piston for reliability in harsh conditions. In 2009 the compact Tavor X95 was selected to gradually replace the M16 and M4 as the standard rifle of Israeli infantry.

Singapore built its own bullpup. Developed over about four years by the Ministry of Defence, the Army and Chartered Industries of Singapore to replace the locally built M16S1, the SAR 21 was adopted as the Singapore Armed Forces standard rifle in 1999. Its features were meant to suit conscript soldiers of smaller stature.

Finish with a national small arms system. Developed by India's Armament Research and Development Establishment and made by the Ordnance Factories Board from 1994, INSAS entered service in 1998 and first saw combat in the 1999 Kargil War. An estimated 700,000 to 900,000 were built by 2019, and India is phasing it out in favor of the AK-203 and the SIG 716i.