It is often said that Hitler personally cancelled the Sturmgewehr development...could that really be true?

Yes! He actually nixed the program three separate times, and the German Army General Staff continued the project behind his back. They knew the rifle was what the Wehrmacht desperately needed if it was to have any hope of victory in the East, and they were determined to bring it to fruition. He did ultimately relent, and approved it to replace the Mauser K98k in early 1944 - but by that time a great deal of opportunity had been lost. Today we will delve into the details of just how the program developed as it pertains to his approval...