Originally Posted by Truc
it has been proven that with only the primer ignited and before the powder lights the bullet is already moving, that is why the small primer is used in Benchrest (205 Federal shoots better because it don't move the bullet) very little flame.
While common with handgun cartridges (in my own tests), larger volume rifle cases oft times will let the bullet stay in place held by the case neck.
How else would my 20 some odd rounds of 7.62 NATO ammo without powder and 190-gr. bullets come back out of the chamber and the bullet had not moved forward one bit? Those bullets needed about 25 pounds of pulling force to dislodge them from the case mouth.