German ww2 field grey uniforms

Hi,

I'm a keen wargamer, and have a project to add a new german force to my list of armies. my question is that was the field grey uniform used throughout the war, or did it stop being used after the early period?. Would I be wrong in painting my troops with field grey uniforms armed with some mp44s for example

People I play with are adamant that field grey was used early war only, and yet I find through my internet searches that this was not true?or am I wrong

Many thanks