I don't think a 150 gr bullet at 2700 fps and change is anything to sneer at, and doubt the 303 is that close.
I've owned 4 Garands and loved them all. Most of the reloading data is safe to use, most but not all. I think the pressure curves matter more than anything and certain powders are desirable.
The M1 may not be quite as accurate as a bolt, but it has 7 more rounds ready to go when the bolt is still being cycled. It is an extremely accurate rifle, and was only suceeded by the M14.
I get a kick out of the M1 because with all those small parts it's just not supposed to be reliable. It is. Very. Modern attempts to better the M1 complain about the weight, but the FN-FAL is even more, and the new SA Sog thingie ll weighs over 10.
It's hard to get that level of power without weight.
I took one deer hunting once and never will again. Too heavy. But it is one of the best shooting, fun, reliable and accurate semi auto rifles around.
I only own it's step child now, the M1A. That weighs almost 9 pounds, shoots .308, and has removable mags.
The Garand is one of the most fun rifles I've ever fired.
I still miss not owning one.
munk