Crack on rear toggle

[Mauser720]

flynt -

I am not an expert; however, I will tell you what I think.

Any metal which is subjected to repeated shocks of one kind or another will eventually experience a change in its molecular structure. The gradual change can eventually result in a crack.

I used to wonder why it was that aircraft frames were said to have a certain useful life when they were in fact made of metal. And the answer is that eventually they do develop cracks due to the stresses they experience over the years. So even an aircraft that looks perfectly serviceable can be a death trap due to these microscopic cracks.

These microscopic cracks can be detected in aircraft parts by placing them in a special dye, and then examing an X-Ray of the part in question.

And I suspect that something similar is going on with our Lugers. Fire one often enough, and eventually something is going to break. It does not mean that you abused your Luger. It simply means that it has reached the point at which metal fatigue has set in at the molecular level.

So that is my opinion; however, perhaps someone who has experience with metallurgy and/or physics can explain this better.