That Wilton C3 with the swivel base is likely around 195-200#. I think mine weighs around 198. So even when you unscrew the dynamic jaw to separate and move two lighter halves of the vise, each will still weigh around 100#.
They are a nice vise, The swivel base locking system is rather weak in my opinion. When you take it apart, inspect the locking teeth or interlocking bumps.. they get rounded off quite easily. You can dress them with a dremel with a small carbide burr.
When using the swivel feature, just make SURE the notches are interlocked and make sure they are snugged down. or they will slip and break the tips of the teeth or round them off.
Nice vise, I'm surprised that there is not the usual C-3 on the side of a jaw tower.
PierceA