FML... I'm done for now with sr's and maybe 240's

[moses]

This is the second time I rebuild an sr and the third time it shit out on me. I don't even know if I want to rebuild another sr. I was suppose to drive half way across America with this motor and it made it a quarter mile. For those who don't remember my first rebuild was after my turbo FODed out so I did headgasket and cams. Then I killed my #1 cylinder with detonation as shown in the pic.

I found out that my fuel pump did not have enough voltage at full boost after thing else checked good so I hard wired it. Then after fully rebuilding it, I broke it in 500 soft miles and ran it at 15lbs (stock boost for actuator) after and everything went good and checked good the night before. I warm up the car for a 2000 mile drive the next day and down the road it shuts off.
I find

then

that little bump is the piston pin! Yeah destroyed! I don't want to fix it right now, I just want to know how it happened? I think spun bearing but I really don't know what that involves. It's not detonation like the first time because it's not melted, it's just in a bunch of big pieces. Y?