Minelab Equinox 600 with 11 inch coil. BLuetooth head set and Minelab pin pointer. My back is the Minelab Explorer II w/ 12 x 9 NEL coil, Minelab pinpointer and Deep woods headphones.
All the Browning machine guns I've seen usually sell between $20,000 - $25,000 in the U.S. but they are fully operational refurbished weapons. For an antique non-operational show piece, I'm not sure.
I have also seen semi-automatic refurbished show pieces sell for $12,000 - $15,000.
I bought one full operational Browning m2 cal 12,7 for ca 3000US. But that is 10years ago.
One good advice is to dont rush the sales of war relics, take you time, and find the one special buyer who will take good care of the relic. Dont be blinded of the price alone.