Not too long ago John Barness (not one of our deeper thinkers) wrote in Rifle "The hot gasses burn up the air because everything burns better in air". I wrote him and asked if oxygen oxide was formed when air burned. So far he hasn't answered yet. The flash is caused by unburned gas (the process is oxygen poor). Unburned gas , and sometimes powder are expelled. How they treat the powder to minimize this I cannot answer. O K Shooter thinks that air space in the case will aid combustion. As you load from almost a case full to a full case the velocity passes through a "flat spot" where the relation of charge to velocity is not constant. I have seen similar results, but don't know if I agree with him.
<br> Now that I've answered this perhaps someone that knows more about powder will pick up on it.
<br>Good Luck!
