Even though he’s gone now, to avoid misleading the public at large re. his claim about semi-autos all being less powerful than bolt guns due to the energy needed yo operate the action, I trawled through Smith & Smith for some data.
The scientific method states that you must only vary one factor at a time. The 3 independent factors are:
Cartridge
Barrel length
Action type
and the dependent variable is the muzzle velocity.
Since we are interested in action type, we must keep the other 2 variables constant. Thus I trawled through looking for pairs or larger groups of wpns with the same bbl length and firing the same cartridge.
Results:
.303" MkVII, 24" bbl: No.4 - 2440fps (24.2"), BREN - 2440fps
fps
6.5mm Jap, 19" bbl: Type 44 carb - 2300fps, Type 11 MG - 2300fps
.30M2, 24" BBL: M1903 Springfield - 2305fps, Garand - 2305fps, BAR - 2805fps, M1919A6 - 2800fps (recoil operation)
Now, his claim in general is false. For the recoil operated MG in question, however, it is true although represents an utterly insignificant 0.17% of MV (compare to the 4" flash gap loss that TINWALT said was insignificant for flash-gap losses in a revolver). This is simple frame-of-reference stuff - with regard to the barrel, the muzzle velocity is still 2805fps. But since the bbl is moving backwards at 5fps, the velocity with respect to the ground is 2800fps.
For a gas operated wpn. the gas operation system HAS NO EFFECT ON MUZZLE VELOCITY.
Ref. his other silly claims regasding this - comparing semi-auto and single-shot cannon is only possible if they are firing the same ammunition from the same length barrel.
I also love his total refusal to remain consistent as to whether ballistic gelatin is valid, and his insistance that a .22rf with a 26cm penetration in gelatin will most likely go throgh a man whilst a 9mm with a 70cm penetration will most likely remain in the body? Especially as 9mm Para FMJ is reknowned for over-penetration and poor lethality.