According to Zaloga in his book, all of the M4s initially deployed in Normandy throughout June of 1944 were the 75mm equipped Shermans (pages 129-131), while the 76mm wasn't deployed until July 1944 when some First Army units started to accept them (page 166).
If there were 100 or so 76mm Shermans sitting in the invasion ships, all they did was take up valuable space.
ack-ack
take up valuable space? What space? Space for more 75mm Shermans? All the reference material I have read say the first Shermans to be fitted with 76mm guns was introduced into the production lines in February of 1944. Now considering that the Americans were stockpiling 75mm armed Shermans long before the 76mm came on line. It would make sense that only a small number of 76mm Shermans were mixed in with the standard 75mm Shermans for the D-Day landings.
Now ...again speculation. I would have to say the the allies knew they would have trouble with the German tanks, why up-gun a Sherman with a British 17lber gun and with a 76mm gun if your current tanks could do the job. The first documented action for the 76mm armed Shermans was in July of that year, a few weeks past the landings. Since the Germans didn't deploy their panzer divisions for 2 weeks after the landing and some up to 4 weeks it would make sense that no real armor battles took place with the 76mm Shermans until operation Cobra. That being said below is more information on the 76mm Shermans indicating that indeed there were 76mm Shermans available for the Normandy landings. There is more information out there that supports the fact there were 76mm Shermans that landed in Normandy then not. All you have to do is look.
Quote;
Sherman tank with 76mm gun:
To increase firepower the Ordnance Department developed the 76mm gun M1 and M1A1, starting in July 1942. Tests showed that the existing M4 series turret was too small to accommodate the extra length of this weapon and the turret of the T20/T23 medium tank was adopted and suitably modified. The 76mm gun installation was standardised and introduced in production lines from February 1944 and vehicles so fitted were available in time for the Normandy landings and subsequent combat in NW Europe. Suffix '(76mm)' indicated vehicles with this gun. A modified 76mm gun M1A1C or M1A2 with muzzle-brake was later introduced.
