Okay, I am one of these guys that doesn't like the M16A1 or A2, so for punch the Trapdoor, but for firepower, I'd take an M1 Carbine, Garand or M14 over the M16 any day. It is fine, but I just don't love it....
(and I am a 45 fan also, building a shooter from GI parts right now in fact, hey! I need a pin for the hammer and the do hicky thingy that hangs from it,
I think I have all the rest of the other parts)
But I think when he said "current rifle" he meant of these two choices, "Would you want the current U.S. rifle, the "trapdoor" Springfield, or the Italian Carcano?"
I am not familar with the Carcano of that time period, but the Trapdoor I have has a hell of a punch and works well. But I think matched SA's and a Trapdoor for every trooper would have made a big difference, plus enough ammo...
Ed