Courtesy of a link provided by Commander Salamander, we find this auction at Government Liquidation:
3,360,000 lbs approx Steel Gun Tubes, the shipping cradles and railroad rails that the gun tubes are sitting on are also included in weight and sale. Demilitarization is a condition of sale for Gun Tubes only.
Property located at Hawthorne Army Depot, NV, 89415. Qty 14ea Tubes and weigh approx 236,900 lbs ea and are 816 inches long, Tube thickness being approx 15in. at the breach and 4in. at the muzzle.
All DEMIL will be performed on site before property may leave.
Clean up of all foreign materials and debris in the surrounding work area are required for buyer to fulfill his responsibility for removal. Local disposal of debris and foreign materials are not permitted.
There are more details and photographs at the link.
Yes, those are 16"/50 Mark 7 gun barrels manufactured for the World War II Iowa class battleships.
These are probably the last such barrels in existence, except for those mounted aboard museum ships like the USS Missouri, shown below at her moorings at Pearl Harbor in Hawaii.
That's a lot of metal - and Navy and artillery history - headed for the smelter. We won't see the like of those guns again.