OK. The 6 pounder comes on the scene in early 1942 with a plain AP and a HE ammo nature. The AP round keeps getting upgraded. Sabot comes along in March 1944, well in time to be used in Normandy. That takes the maximum armour penetration from a baseline of 88mm up to 142mm. The US also buys the six-gun, but it doesn't do the ammo upgrades and as a result doesn't get value from the weapon except when units beg APDS rounds off the Brits, which they do whenever they can because they don't want to die.
The six-gun is installed in a variety of British tanks. As you have discussed, Shermans start to flow into the RAC, to begin with in the Middle East. They bring with them the US 75mm. The combination of US pushing of Sherman, and after-action reports wanting a better direct fire support weapon, leads the UK to accept Sherman and also to introduce the ROQF 75. The important point here is that the ROQF 75 uses the same ammo natures as the US M2/4/6.Per Wikipedia, there is never a decent AP round for the M2/4/6 or therefore the ROQF, while there most certainly is for the six gun and the 17. In fact, the M61 AP shells were even delivered without the burster fill, so their ballistics may also have been screwy if the weight in the tail wasn't replaced with something.So. HEAT or whatever doesn't turn up in time to be relevant, but sabot certainly does. In fact, run the tape back to Villers Bocage.Wittmann kills a Sherman, another gets stuck across the road due to its shitty drivetrain so the rest of the squadron can't gang tackle him. He rips into the RHQ squadron, and then...well, Bill Cotton and a handful of Jackets scrabbling about like untermenschen get a mobility kill and he wanders off leaving his crew. The point here is that the Jackets' AT platoon are loaded for bear or rather tiger with 6 pdr APDS while the CLY tanks have nothing like it. Cotton pulls this off again and again through the day. It happens again in EPSOM - German armour smashes everything until it hits an infantry AT platoon and then it, er, doesn't.Question. Why wasn't there a sabot round for the 75? A 75 round weighs about as much as a 6, so the energetics ought to be OK. The Americans never got it for their own 6s - couldn't their industry manage it? In which case, why did ROF not make one as they obviously could? The British were clearly aware they were short on tank killing capability, hence the effort to upgun Shermans and M10s.Further question. The requirement for better suppressive fires out of a tank wasn't bullshit - engaging German anti-tank guns was something all armour that fought them needed to do. It turned up as a requirement from Tunisia and AFAIK Sicily - is there some really fascinating deep history of the landscape you're going to tell me about? Or is it more that 1st Army's artillery fire control and forward air control was a bit wank compared to 8th, which after all had learned the hard way?
Apropos of not very much, Nineties club music before the break, technology (and the secret history of tanks and the Norman landscape) after the break.
No, wait, not quite done being frivolous yet.