Lloyd indeed gives a "general statement" that is close. However, there are many variables to your question; rifle or handgun, what cartridge, twist of barrel, accuracy requirement, etc. For example; with a 6" barreled .357 Magnum I get 200-200 fps more velocity with equal accuracy using GC'd bullets. In regular rifle cartridges with standard twists I get 500-800 more fps with equal accuracy using GC'd bullets. With my .308W with a 14" twist barrel I get closer to 1200 fps more velocity with equal accuracy using GCs. Then there are the excepetions; in my trapdoor 45-70s I get equal accuracy with either type of bullet as the strength of the rifle is the limiting factor. However in my Siamese Mauser 45-70 I gan get 500-700 fps more velocity with equal accuracy using GCs. All the above is why you got a "general statment" from Lloyd.
Larry Gibson