|Place of origin||United States of America|
|Weight||3.1 kilograms (6.8 lb)|
|Length||546 millimetres (21.5 in)|
|Barrel length||292 millimetres (11.5 in)|
|Action||Gas-operated, rotating bolt|
|Rate of fire||950 rounds/min|
|Effective firing range||300 m|
|Feed system||Various STANAG Magazines|
The LR 300 is an American assault rifle and conversion kit designed and manufactured by Z-M Weapons. It is based on the AR-15 platform and is broadly similar to the United States service rifle, the M16.
The weapon is touted as an 'excellent entry weapon system' indicating a suitability for military use in close quarters battle which often involves aggressive and rapid building entries requiring a compact yet powerful selective fire weapon.
Also notable is the rifle's capability to use a fully folding and adjustable skeletal stock. Most AR-15/M16 rifle variants have a thick, cylindrical recoil buffer tube, more properly called the receiver extension, that protrudes approximately 20 cm straight back from the rear of the receiver, and the firearm cannot operate without it. This normally precludes the use of anything but fixed or telescoping stocks. The LR 300 however uses an adapted version of the AR-15's standard direct impingement gas operating system which removes the need for a receiver extension.
The gas key is extended beyond its normal length to form an operation rod, such as an M14 or AK47, extending into the top of the forward handguard. The gas key contains the return spring which is fixed between the front of the receiver and the collar at the front of the gas key. The gas tube runs backwards from the gas block in the front sight base and enters the gas key. In this way when the firearm fires at least some of the combustion gases from inside the gas tube are vented into the handguard area rather than the receiver. This means the standard buffer assembly is not required at the rear of the weapon, allowing a folding stock to be fitted to reduce the overall length of the weapon, and reduces gas fouling in the receiver.
LR-300MLs have flat top receivers with Picatinny rails, allowing them to be used with multiple types of sighting systems. The trigger, along with the charging handle, forward assist, magazine release and bolt hold release are identical to those of the AR-15. The barrel has a 1:9 twist ratio, is chrome lined, and the muzzle is fitted with a Phantom flash suppressor.
- LR-300 ML-A: Military / Law Enforcement model (Selective Fire version). Has an 11.53-inch [293 mm] barrel, aluminum forend, and fires single shots or bursts. $1,815.00
- LR-300 ML-N: Military / Law Enforcement model (Selective Fire version). Has an 11.53-inch [293 mm] barrel, Nylatron forend with attachable Picatinny rails, and fires single shots or bursts. $1,840.00
- LR-300 SR-A: Sport Rifle model (Semi-Auto Fire version). Has a 16.49-inch [419 mm] barrel, aluminum forend, and fires single shots. $1,765.00
- LR-300 SR-N: Sport Rifle model (Semi-Auto Fire version). Has a 16.49-inch [419 mm] barrel, Nylatron forend with attachable Picatinny rails, and fires single shots. $1,788.00