The Barrett MRADELR .375 EnABELR "EB" Barrel Maker Kit is a component set designed for builders creating a custom barrel assembly for the MRADELR platform. Intended for the .375 EnABELR cartridge, the kit provides the essential interface parts required for proper bolt and barrel integration, allowing a qualified gunsmith to fit a custom barrel blank to the system. Included components are: barrel extension, barrel‑extension jam nut, bolt, ejector roll pin, ejector spring, ejector, extractor, and instruction card, with the firing‑pin assembly intentionally omitted per the NFP designation. This kit supplies the foundational hardware for a precision barrel build while allowing all final barrel specifications—length, twist, rifling, and muzzle configuration - to be determined by the builder.