Trigger shaping question

[wvmtnman]

I am wanting to shape the front trigger, on a Davis set trigger, but I am unable to drill through the steel.  I anealed it but the drill bit will not go through the metal.  I am not real familiar with the various types of metal bits out there or anealing metal.  Any suggestions would be helpful.
                                                                           Brian

[LRB]

  Have you tried a colbalt drill bit? If that doesn't cut it, a carbide bit will, but if you can heat it red hot, and drill while it's red, any bit will go through like it was butter. Carbide bits are costly, and very brittle.

[Lucky R A]

Davis triggers are cast of an air hardening alloy.  Simply heating and allowing it to cool will will result in it being extremely hard and brittle.   To anneal you have to heat the part and hold it at temperature and then cool very slowly by packing in some type of insulating material.