Went to R/S today to pick up some BNC connectors to make a short coax
patch
wire.

Was somewhat surprised to see that they only carry, now, the "screw-on"
variety.
No more soldered ones.

Apparently you insert the stripped end of the coax into the connector, and
twist a portion of the rear
of the connector barrel which clamps the braid.
My guess is that this probably is OK for the braid, but I can't imagine
how
it connects, relaiably, to the center pin.

Looking at it in the package, it seems the coax wire just pokes into the
center pin, and that's that.
Maybe they expect gravity to make a contact.

Seems like this would make a really poor connector, but perhaps I'm too
old
fashioned in thinking that
the only good contact is a soldered one.

Am I missing anything here ?

Do they actually work ?
Work good enough for a receiver's coax run ?

Almost nothing from RS works very well . They do have some already built
things with a good reputaion but you have to be careful even then.