First time firing my new Bushy Shorty today, the mag fell off, straight down on the bench, and when I looked down, the mag catch was beside it. Upon inspection the rod that press fits into the mag catch had detached upon firing and had flew out with the mag release button and spring.  I found the rod still screwed into the button but lost the spring.  I don't understand how this happened.  Everything seemed to be fine with the mag catch/release assemby before this.  Anyone have something like this happen?  Right now the rod can easily be removed from the mag catch by simply twisting.  It turns easily.  An ex-army national  guard guy shooting next to me who helped look for the parts said he remembers the rod peice as being one peice of metal with the mag catch.  

I have seen them both 1 piece welded and threaded.

I talked to Bushmaster today.  They said that the rod part of what they call the "magazine catch assembly", is not supposed to be rotatable with bare fingers (as mine is).  Appearently mine was defective from the beginning (too loose) which is why it came apart.  Bushmaster told me to send it back for a replacement.