Best not to use a "vamint bullet".
Something along the lineo of an Accubond, Partition, Interlock, ELD-x, TSX, Core-Lokt etc would be preferable.
Shot Placement trumps when it comes to pigs. My favorite shot is this.......
Think of drawing an imaginary line between the ear and shoulder. Try to place your bullet about 2" below the ear along that line. That shot severs the spine, they drop and paddle. No tracking.

270 Winchester, 130 Gr. Nosler Accubond.
I prefer a larger heavier bullet when shooting hogs in case I make a bad hit, so I will have two leaky holes shedding blood in case I decide to track.
However, with proper shot placement 6mm or 6.5 mm will work just fine.

240 Weatherby, 80 gr. Nosler Partition.
ya,
GWB