lower compressed air volume/pressue = lower power

Harder rock types usually requires the use of
diamond bits from the higher matrix groupings.
 
BROKEN rock types usually requires the use of
diamond bits from the LOWER matrix groupings

  Group 100 - Coring bits for powerful high-torque drills
                      Drill very well in extremely abrasive rock

  Group 200 - All purpose coring bits for high load drilling
                      Drill very well in fractured formation

  Group 300 -  Coring bits for lower powered medium load drills
                       Drill very well in medium hard formation

  Group 400 - Versatile durable high penetration coring bits
                      Drill very well in changing formation

  Group 500 - High penetration coring bits in all rock types
                      Drill very well in fine grained hard rock

EXCESSIVE HOLE DEVIATION usually requires the use of
diamond bits from the higher matrix groupings.

a Less powerful DRILL usually requires the use of
diamond bits from the higher matrix groupings