The Brit. 200 gr. .38 S&W load was simply a way to rationalize a small lighter weight .38 over the heavy .455.
Dave Arnold, of G&A, who was a South African policeman before coming to America, wrote how once a policeman was shot with the .38 S&W 'manstopper' 200 gr load from a nother policemans gun and his greatcoat stopped the slug! He also said the bulllet would bouce off trees.
As for dwell time, this has to do some sort of 'energy dump' theory. The longer time (we are talking about .034 seconds difference in times) supposely would cause more shock. I really don't know how they tested this as I have never read of the Brits. doing any kind of test on animals or caviders or just anything to check this out. As I said, it was more of an excuse to rationalize the smaller gun and lighter ammo (read cheeper gun and cheeper ammo.)
The FMJ 180 grain load was indeed substitued for the 200 grain lead load. It was even worse. Now maybe, just maybe the 200 grain load might tumble, and thus create a larger wound (presuming it got through clothing), but the 180 grain load, being shorter, was more stable and thus no tumbling.
While I'm no fan if FMJ, if I had to pick that then the gun would be .40 at the least, and more like .45 (unless any of you know of a .50 ACP round out there for the 1911.)
Come to think about it, I wish Glock had just made their round a .50 GAP, and not a .45. I would pick that gun up in a flash.