BCM offers the Vltor buffer with their extension tube and other parts as a kit ... https://www.bravocompanyusa.com/BCM-Intermediate-Buffer-System-A5-Kit-p/bcm-intermediate-shk.htmDo some research on the Vltor A-5 system . It's a hybred between the carbine and rifle recoil set up . It is proprietary though.
Do some research on the Vltor A-5 system . It's a hybred between the carbine and rifle recoil set up . It is proprietary though.