I don't think that is too surprising. .45s are big slow bullets. Good for hitting a bad guy, but not so good for shooting through stuff before impacting said bad guy.
I have a 1911 that won't have that problem it's a GRIZZLY 45 WINCHESTER MAGNUM, it's a 45 caliber 230gr. bullet traveling over 1400 FPS
I thought the 5.7 was designed specifically to defeat light armor?It makes me wonder how 5.7mm would compare.