Novel compounds, N,N-bis-N,N-bisurea and N,N,N,N-tetrakisurea, suitable for use in preparing N-acyl aminocarboxylic acids that can be readily converted to N-glycine are provided. The system includes the hand guard having a proximal end configured to engage a forward end of a receiver of the firearm. When closed the container retains its rectangular shape but it has a slanted shape when opened and the top is stored below the bottom, such that the front of the container is lower than the rear of the container.