Does anyone know of a solution to mount the a STOCK ADAPTER to fit a Mil-spec buffer tube? According to Tooth and Nail, they "do not recommend cutting the stock on the BR-99, as it is made much different than the MKA, it's basically hollow where the stock adapter fits. We could cut it for you if you wish and install the adapter, as long as your aware up front."
"As for the grip, the BR-99 receiver is solid there, the grip adapter will not work without extensive milling to attach it."
Their "website lists which parts will fit the BR-99."