resizeboxmodule bagtabularModule:

\begin{
    table} \label{
    tab:x}
\caption{
    mytable}
\centering
\resizebox{
    .5\textwidth}{
    !}{
      % Here 1/2
  \begin{
    tabular}{
    rrr}
  A              & B            & C \\
  \hline
  A1             & B1           & C1 \\
  A2             & B2           & C2 \\
  A3             & B3           & C3 \\
  \end{
    tabular}
}  % Here 2/2
\end{
    table}

\end{
    document}