Quote Originally Posted by tacfoley View Post
It's because BP is an explosive compound, and the air contained in the space would enable an 'explosive front' to generate, causing, mostly, massive damage in a confined space such as bulging of a chamber, or bulging/ringing of an barrel - or at it worst, a burst barrel.

By contrast, nitro propellant compounds do not detonate, but burn, albeit quickly, as far as WE are concerned, but slowly as far a actual physics are concerned.
Thanks for the reply. I can understand the possibility of an explosive compound detonating in a contained air environment causing a problem, but wondered if the same situation would arise when using a black powder substitute such as Pyrodex or 777 which are classed as propellants rather than explosive compounds.

Do you believe in practice that not seating the projectile really close to the rifling would have a detrimental effect on accuracy ?

Brian