I have a friend with a transferrable HK21 built on a RR HK91 (shelf gun) and an excellent condition FMP kit. This is a Vollimer marked gun built by Dwyer. It has been test fired only, like a real 20-40 rnd test not a 2k round test. Everything looks mint on it and it's painted a nice OD green. He's looking to sell and not sure of current pricing. The last couple I've seen sell were MM23's or 21e sear guns so I'm not sure what to tell him. Any input would be helpful.