Not enough information, Question 1 what are you using as a core drill? #2 what RPM is the drill # does the core drill have any set to the teeth to allow the hole to be larger than the body of the drill.
Annular cutters work great for things like this but are expensive, and just like a deep hole saw they should be run at a low RPM , High velocity air blown around the cut will help to blow the chips out of the hole the chip granules get between the drill body and the base material which causes friction and heat
A carbide tipped hole saw would work well I should think since the teeth protrude outside of the body but still need the chip removal A mist cooling set up like used on mills would do well also just plain water and air possibly 100 to 200 to one ratio this will cool as well as blow out the chips. Others may have better ideas