Posted for "Tom Gourley" <tom.gourley@verizon.net>:

 A solid conductor may be more prone to crack if it's subjected to vibration
or bending and there is some sort of stress riser, like a nick in the
conductor.  Offhand I don't know if all RG400 is constructed the same, but the
expensive stuff from Pasternack ($2.61/ft) uses silver plated stranded copper
for its center conductor.
 
 Tom Gourley