I had a Uberti SAA the same way. Gun fell apart when I was shooting it. My theory was it was assembled dirty, mill shavings or something under the shoulder.
I had to set the barrel back almost another turn.
Everything on that gun fell apart or was loose, must have been assembled by a greenhorn on Friday afternoon.
After basically rebuilding the whole gun it has served me well for a few years now.
I had one gun that the barrel came loose on and I did the red loctite thing as Pettifogger said.