I have pushed PB's out through the breech. It will probably ruin them. Since they're gonna be ruined anyways, why not use a bullet puller, if convenient? That's the easiest way. I've done it and think it's much easier than unscrewing the breech plug, etc. Maybe it isn't. I guess it's a personal thing.

I have reused bullets and can tell you that they will fall far outside the group. I had a 2 inch group and then shot a reused bullet that was removed by a bullet puller. It fell way out. I suppose less damage would be incurred if you pushed the bullet out from the back. That would hardly do anything to flight. I've found out that. That's the best way, the bullet puller is the easiest.

that's my two cents