 Before long American military agencies and designers had accumulated sufficient experience to forge ahead on several points.In the field of tank armament the American 75 mm and 76 mm dual-purpose tank guns won the acknowledgement of British tank experts.Detailed design characteristics for the M4 were submitted by the Ordnance Department on 31 August 1940, but development of a prototype was delayed while the final production designs of the M3 were finished and the M3 entered full-scale production.