Is the elaborate test referenced by Garwood corroborated by any other source?
'The Field' magazine perhaps? Anyone?
It's a very vague report notably lacking in particulars.
Far as I'm concerned without verifiable references it didn't happen.
Jones, perhaps you ought to pose that question to this forum's own "Crossed Chisels" (David Trevallion). In their book "Shotgun Technicana", Trevallion and the late Michael McIntosh start out with "Acknowledgments"--which includes a photo of Mr. G.T. Garwood (Gough Thomas). They give him special mention. Why don't you ask Mr. Trevallion if he thinks Thomas knew what he was talking about? And perhaps, if you don't care to take that risk, you can produce evidence--from a scientifically conducted test--that slow burning powders produce less recoil than fast-burning powders. And remember, as I pointed out above, that you're starting in the hole--since the formula for computing recoil tells us that the more powder you use--and you always use more slow-burning powder to get the same velocity for the same shot charge--the more recoil you get.
