What we are going to do here is to polish (not alter) some parts to make the trigger pull (which admittingly is a bit different) smoother. I’ve also included the extra steps to completely disassemble the gun and get it back together again

Read it here.

If the Glock firing pin is partially retracted and the Springfield XD is fully retracted we could draw the conclusion that the Glock is half-cocked while the XD is cocked and locked. Both will fire if there is an accident. Both have safeties in place to prevent this from happening. If the only unique safety on the XD’s is the grip safety, how does it work? It looks like the grip safety on the 1911, but it definitely does not quack like the same duck.

More here.

mechanisms to ensure the pistol does not fire a round unless the trigger is pulled, ie. not when dropped, knocked etc.
Rob has written a interesting blog entry explaining how the internal Glock safeties works.

Understanding how your weapons safeties work is also of critical importance. Glock, even though it has no external safeties is no exception.

So that out of the way we can begin discussing how Glock is looking out for you. As you may know the firing pin is under 2/3rds pressure when the slide is charged. As soon as you place a round in the chamber there is pressure, and therby a possibility, however remote, that the round may go off.

More here.

UPDATE: Famous Guns has more information here.

Here is a very good animation showing the AK-47 internals and how it operates. To view the animation thumbnail below to watch it:

Warning, it is quite large (2.3mb)

Unfortunately I do not know who the author of this animation is.