A better US / British AT gun

What if the British and US did with the 6 pdr / 57mm M1 antitank gun what Britain did with the 6 pdr tank gun? That is, they bore out the towed gun to 75mm and use US 75mm ammunition for the M3 gun with it.

This would give the towed gun a great HE round making these guns far more valuable to the infantry as support pieces. The question is, could the towed version's mount take the stress? If so, it gives a US infantry regiment, for example, 18 75mm antitank guns that have a vicious HE round. That would make these guns far more valuable to them as support pieces.