Hunterseeker has one now on his shape ways.
Im not sure how well the stock chamber would work on a r hop and dout it would work well on a er hop as the nub is very small and cant be extended without severally modding the chamber
Im not sure how well the stock chamber would work on a r hop and dout it would work well on a er hop as the nub is very small and cant be extended without severally modding the chamber