As a very general range, somewhere between $12,000 and $17,000. Mostly, it will depend on what type of conversion was done. If it is a registered receiver gun done by adding an autosear but using the host weapon's serial number, it would generally be least desireable. A conversion using a registered autosear, where the sear itself is the registered part and the host weapon is only a host, would fall in the middle of that range. The conversion that is most like a factory full auto gun, and therefore most desireable, would be a registered receiver gun where the front pin hole was drilled in the receiver creating a "registered receiver push-pin" conversion. This type of conversion can use factory HK trigger groups and is typically most expensive.