M110K5

The evolution of the Universal Rail Extending (URX) begins over 20 years ago with Knight’s Armament pioneering the Modular Weapon System. Knight’s URX is a lightweight, free-floating, continuous top rail system that was designed to give a shooter the most diverse amount of placement options for any accessories they deemed helpful.

In an effort to relieve all weight, contact and stress from the barrel, the URX component was designed to be free-floating. This means that your barrel is not supporting or coming in contact with the rail system other than at the receiver. Under high firing rates, when the weapon’s barrel is heating up and undergoing greater amounts of stress, this system ensures accuracy is not affected by mounted accessories or a shooter’s manipulation of those accessories.

Several variations of the URX are available depending on your needs. They come in a variety of lengths, from our URX Carbine at 7” to our URX 3.1 7.62 at 14”. Knight’s latest systems are the URX 3.1 systems which feature a flat continuous top rail, several inches of mounting rails at the fore and rear ends of the sides and bottom, and slick sided portions in the middle sections. These slick sided portions provide a slimmer diameter for grip as well as an overall reduction in weight. Some of our other models, such as the URX II variations, include full length side and bottom rails and integrated front sights. These components provide the most amount of options with the least amount of interference.