i've talked with different engineers at different powder Companies. i still get 2 completely different answers. my question is...when the powders ignites in the chamber, how long, or more importantly, how far down the barrel does the bullet travel, to burn the powder? i've heard it takes long barrels to burn all the powder in our big overbore cartridges. i've also heard the powder burns in the first 3-5" of bullet travel. i've heard you can spread a sheet out and see all the powder that doesn't burn with the short barrels. i've heard the powder is all gone in the first few inches of bullet travel and the pressure just decreases until the bullet departs from the barrel. i've heard both scenario's from the ENGINEERS! WHICH IS IT?