Pic 1 shows a blue tip bullet which is mildly magnetic. I think it is a M1 Incendiary, the magnetic reading would be the steel case inside of the bullet. The depth of the hole should be to the tip of the bullet if the compound has been removed. I can only assume that the drilling that someone did would have caused the incendiary compound to fully burn out. It does not look like the compound was ignited and there is no heat staining on the bullet case and the blue tip is not discoloured by heat. So what do I have?
Pic 2 The blue paint on the bullet is more than a tip colour, the paint extends 15.1 & 15.2mm from the tip down the bullet body. In Chris Punnett’s book it mentions St Louis incendiary with .303 bullets swaged into 30-06 cases. I dont think they are 303 bullets. They are very magnitic.