September 21, 2023: All British infantry are to receive the new L403A1 assault rifle if the various special forces units receiving it find its performance equal or superior to current assault rifles used by British troops. L403A1 is not a radical new design, but one that utilizes features found useful by troops and with unpopular features eliminated or modified into something acceptable.

L403A1 uses NATO standard 5.56mm ammunition and 30 round magazines. The rifle is lighter, at 3.12 kg (6.9 pounds), than existing 5.56mm automatic rifles. The barrel is equipped with a suppressor and even with that the rifle is only 869mm (34 inches) long. The barrel is designed to function consistently despite temperature extremes and has a fluted outer shell that enables users to safely handle it no matter how hot the barrel gets. The rifle comes with a thermal sight that can also act as just an optical sight.

Britain has already purchased 1,630 L403A1s for its special operations brigade. These cost $11,000 each. The price would go down for larger purchases. Ultimately the L403A1s could replace the SA80, which has been the standard infantry rifle since 1987. The SA80 has been unpopular with the troops because it’s a bullpup design, first appearing in 1977. These bullpups were an effort to provide an effective rifle in a small package for use by vehicle crews, special operations troops and support personnel who did not need a full-size combat rifle. The bullpup design allowed the designers to get a 518mm (20.4-inch) barrel on a 780mm (30.7-inch) long rifle. Many bullpups featured even shorter barrels. Contrast this with the M16A2, which has a 508mm (20-inch) barrel, the rifle is 1008mm (39.6)-inches long. Both rifles fire the 5.56mm NATO round, and use 30-round clips. Nine inches might not sound like much, but for a soldier in a vehicle, nine inches can be as important as nine miles. A smaller rifle is lighter. Bullpups are also more compact. In vehicles like tanks or IFV (Infantry Fighting Vehicles like the British Warrior or American M2 Bradley, space is at a premium.

For a while Bullpups were very popular. Early models like the Austria Steyr and France's FAMAS saw considerable service as well, with the former being adopted by a number of countries; including Austria, Saudi Arabia, Malaysia, Oman, Ireland, New Zealand, and Australia as well as the US Coast Guard. The FAMAS served with the French, UAE, and Senegalese forces.

There were problems with the Bullpup design including accuracy and awkwardness for troops initially trained on full-size assault rifles. Spent shells left the rifle close to the soldier’s face if aimed fire was used. This included ejected ammo combustion gas which can momentarily disrupt eyesight. Left-handed users often had ejected cartridges ejecting into the face. As a result, when used in combat the troops preferred to use automatic fire, which quickly emptied the 30-round magazine. Efforts to remedy these problems were never completely successful and the bullpup fell out of favor in many armies. China used a bullpup design as an infantry for over twenty years before reverting to a full-length rifle for infantry units. Several other countries did this, but usually kept the bullpups for support troops and vehicle crews.