$ perl -MDevel::Peek -e'push @$a, $_ for qw( a b c d e ); Dump($a,1); $a=[@$a]; Dump($a,1);'
SV = IV(0x817bc44) at 0x817bc48
  REFCNT = 1
  FLAGS = (ROK)
  RV = 0x816c158
  SV = PVAV(0x816d1c8) at 0x816c158
    REFCNT = 1
    FLAGS = ()
    ARRAY = 0x8177928
    FILL = 4                       <-----  5 visible elements
    MAX = 11                       <----- 12 elements allocated
    ARYLEN = 0x0
    FLAGS = (REAL)
SV = IV(0x817bc44) at 0x817bc48
  REFCNT = 1
  FLAGS = (ROK)
  RV = 0x816cea8
  SV = PVAV(0x816d1dc) at 0x816cea8
    REFCNT = 1
    FLAGS = ()
    ARRAY = 0x8183cb8
    FILL = 4                       <-----  5 visible elements
    MAX = 4                        <-----  5 elements allocated
    ARYLEN = 0x0
    FLAGS = (REAL)