Big - the blue tinge comes after the case is quenched in water. Brass is wierd stuff. When heated and quenched, it gets softer - opposite of steel. You don't need or want to get it red hot. The easy way is to hold the case by the back (near the web) with your fingers. Place the neck into the propane torch flame and rotate. When the case gets too hot to hold, open your fingers and let it drop into the 10 quart bucket of water you have placed right under the torch flame. The neck and shoulder of the case will usually be discolored.