Z-M Weapons LR-300-SR semi-automatic rifle, late production version (circa 2006)



Para USA Tactical Target Rifle, with buttstock open

Specifications for Z-M Weapons LR-300 rifles

	LR-300-SR	LR-300-14.5	LR-300-ML
Caliber	5.56x45 mm / .223 Remington
Action	Gas operated, rotating bolt, direct impingement
Overall length	946 mm / 37.25"	896 mm / 35.25"	820 mm / 32.25"
Barrel length	419 mm / 16.5"	368 mm / 14.5"	293 mm / 11.5"
Weigth	2.95 kg / 6.5 lbs	2.72 kg / 6.0 lbs	2.54 kg / 5.6 lbs
Rate of fire	--	--	950 rounds per minute
Magazine capacity	30 rounds

Specifications for Para USA Tactical Target Rifle

Caliber	5.56x45 mm / .223 Remington
Action	Gas operated, rotating bolt, direct impingement
Overall length, stock open (folded)	838 mm (667 mm) / 33" (26.25")
Barrel length	419 mm / 16.5"
Weigth	3.45 kg / 7.6 lbs
Magazine capacity	30 rounds

The LR-300 rifle was manufactured by the small US-based company Z-M Weapons between 2000 and 2007, when all rights for the design were sold to the Para USA, the US-based subsidiary of the Canadian pistol maker Para-Ordnance Ltd. The reworked LR-300 rifle will be sold in USA as Para Tactical Target Rifle, with first sales sheduled to "early 2009".
Original LR-300 (LR stands for Long Range) rifles were designed by Alan Zitta as an upgrade to the well known and popular M16 / AR-15 rifle. In fact, LR-300 and Para TTR both use standard AR-15-type lower receivers; only upper receivers are different and contain patented modified gas system. The key reason for tha modification was to prowide AR-15-type weapon with capability to mount side-folding stock rather than partially collapsible M4 carbine-type stock. Z-M Weapons intended its rifles mostly for military and law enforcement personnel, by offering LR-300-ML weapons with short barrels and select-fire capability. Civilian (semi-automatic only) versions also were offered to general public, but at prices well above the average price of  AR-15-type rifle. It is not known yet if the new Para Tactical Target Rifles will also be offfered in military (select-fire) version or not; current Para USA advertising suggests that only semi-automatic weapons (and upper receiver conversion kits) will be offred, at least initially.
The LR-300 rifle is gas operated, and utilizes modified Stoner-type direc gas imingement system. In this modified system, the gas key is extended forward to form the tube, that protrudes forward from the receiver and into the handguard. The protruding part of the gas key tube is used to host the bolt return spring, which is placed between the front receiver wall and the collar at the front of the gas key tube. The gas tube, which runs rearward from the gas block / front sight base, is strengthened as its rear end floats freely to enter the extended gas key tube when bolt group is in the battery. That way, at least some of the hot gases from inside the gas karrier are expelled outside the receiver and into the inner handguard area, through the extended gas key tube, once it has left the gas tube during the bolt group recoil movement. Additional benefit of this system is that it allows the bolt carrier to be made twice as short compared to the standard AR-15-type bolt carrier. In turn, this results in the fact that there's no need for the recoil buffer tube, which is normally protruding backward from the AR-15-type lower receiver. Because of this feature, most LR-300 rifles are fitted with side-folding shoulder stocks, either sceletonized non-adjustableones made from metal or polymer ones, adjustable for length of pull. Otherwise the LR-300 is similar to the  AR-15-type weapons and has similar trigger / safety arrangements, magazine housing and bolt stop device.