by Hoot » Sat Mar 12, 2022 10:31 pm
What holds the bullet back until the powder can get going is neck tension, along with a little bit of Newton's 1st Law. Neck tension is achieved when the case tries to push down on the bullet jacket and that jacket pushes back, causing friction. Plated lead bullets deform when pushed and stay deformed due to the thin plated on jacket, as opposed to a thicker jacketed cup and core bullet. When the primer ignites there is a shock wave that move forward, along with the flame. With poorly retained bullets, that shock wave pushes the bullet out of the case before the powder really gets cooking. The sudden drop in pressure retards the powder's release of energy. The bullet jumps forward into the lands where it meets resistance to any further forward movement and the pressure rebuilds, albeit slowly, until the remainder of the powder's energy can sufficiently rebuild and continue pushing the bullet (hopefully) down the barrel. Sometimes it does and sometimes it doesn't have enough uumph left to get the job done.Sometimes the powder doesn't reignite and you're left with a yellow blob in the chamber and umma gumma everywhere, along with a bullet lodged in the bore = Bad JuJu!
It's not just the the concern over plated bullets shedding their jackets to leads us to advise against using them.
Hoot
In Theory, there is no difference between theory and practice. In Practice, there is.