\listfiles
\documentclass{article}
\usepackage[a6paper]{geometry}
\usepackage[acronym, style=listdotted, toc]{glossaries}  
\makeglossaries

\newacronym{SOEP}{SOEP}{Sozio-Oekonomisches Panel} 
%\AtBeginDocument{\setlength{\glslistdottedwidth}{.5\columnwidth}}
\begin{document}
\printacronyms

\section{Test}
\gls{SOEP}
\end{document}
