[Tex/LaTex] Adjusting separation between matrix entries

Question

I have a very large matrix which overflows in the margin. I would like the matrix to fit inside the margins, but I would like to do this without rescaling it, and also without affecting other array-type entries. Is it possible to adjust the horizontal separation between the matrix columns for one object?

I have tried doing the following:

\documentclass[12pt]{article}
\begin{document}
\begin{equation} 
A  = \setlength\arraycolsep{2pt}
\pmatrix{ A & B & \dots & C & D & E & \dots & F \cr
A & B & \dots & C & D & E & \dots & F \cr
A & B & \dots & C & D & E & \dots & F \cr
A & B & \dots & C & D & E & \dots & F \cr}
\end{equation}
\end{document}

but changing \setlength\arraycolsep{2pt} does not actually change the spacing.

Answer 1

Here I use a TABstack. The intercolumn gap is settable, here to 2pt. The interrow baselineskip may also be set with \setstackgap{L}{<length>}.

\documentclass[12pt]{article}
\usepackage{tabstackengine}
\setstackEOL{\cr}
\begin{document}
\begin{equation} 
\setstacktabbedgap{2pt}
A  = \parenMatrixstack{
A & B & \dots & C & D & E & \dots & F \cr
A & B & \dots & C & D & E & \dots & F \cr
A & B & \dots & C & D & E & \dots & F \cr
A & B & \dots & C & D & E & \dots & F
}
\end{equation}
\end{document}