* NEW VERSION WORKS WITH LARUE HANDGUARDS* The MUR is a rigid MilSpec flat-top upper receiver made to fit all AR15/M16/M4 rifles and carbines. The MUR was developed to give the customer a MilSpec correct upper receiver with a thicker wall making the MUR upper receiver a more rigid platform. A more rigid upper receiver will increase accuracy and reliability while extending the life of interfacing components such as the bolt carrier group and barrel assembly. The main benefit of the MUR is it's dimensionally correct. Unfortunately, with the current war effort, a number of AR suppliers are rushing through production, bypassing critical dimensions which will either make or break the reliability and accuracy of the weapon. With the existence of the MUR, you'll receive the best and highest quality upper receiver available on the market today. The MUR comes in two models: one with a Bolt-Assist/Shell-Deflector and the second with a Shell-Deflector only. Being a modular design, Vltor offers the service of exchanging the Bolt-Assist assembly for a Shell-Deflector only assembly and vise-versa. All MURs feature a MilStd-1913 scope mounting rail and come equipped with an Ejection-Port, Dust Cover Door. ** Vltor will not sell the Bolt-Assist/Shell-Deflector assemblies separately. Vltor will offer the service of conversion only. Installation and legal note: The installation and the assembly on the MUR should be performed by a qualified gunsmith and/or certified armorer.