The black end cap on the guide rod holding the spring on came off and I can't find it anywhere. The rod and spring assembly are stock and brand new. Is it safe to put it together as is and shoot it? Would it be better to get a new captive guide rod or a non-captive guide rod? It seems a lot easier to use a captive one. Should I replace the spring at the same time? If I can't shoot it as it is then I've got to get a replacement fast.