Sounds like your '94 has a rear sight that is dovetailed into the barrel. Most, if not all were. Yes, it will drift out.
As to detonating a round while loading. I think, as long as you are using round nose or flat nose bullets designed for the cartridge, it's pretty much impossible.
I severely doubt it would happen with spire points, but it IS possible, so don't load spire points, unless it'as one only in the mag and one in the chamber.
Many spire point designs are for higher velocity cartridges anyway, and may not work well in the 30-30 on game.
I am a big fan of the receiver sight myself. If you want something bright out front, try one of Williams "Fire sights".
Scope on a '94? Nope, couldn't do it. I just can't ever see myself doing that to any of my '94s. Personal thing I guess.