No problem, I always enjoy firearms trivia. For instance, the .223Rem began its life as the .222 Special, which was developed by none other than Eugene Stoner. There were already a few other .222 rounds in existance (like the .222Win), so the round was retitled the .223Rem in order to avoid confusion.
Also, to expound on the difference between the 5.56 and the .223, since the 5.56 has a longer neck, it could jam in a .223 barrel. There's also more powder, so, when fired, that puts the pressure out of SAAMI specs. Therefore, it's safe to shoot both 5.56 and .223 out of a 5.56 barrel (which specs most are made to, anyway), but NOT 5.56 out of a .223 barrel.
Can the same bullet be loaded in a 22-250 and .223? Is the brass of a 22-250 larger or smaller?