U S Army traing films demonstrated the penetration power of the .30 carbine under normal conditions, and it seems to have worked quite well against the German helmet. The same helmet would stop a .45 ACP (from a pistol) at medium ranges.
Its not unlikely that some Chinese troops wore captured U S Doron flak jackets or captured Japanese armor from WW2 occupying troops. I've seen photos of Japanese officers in China wearing metal breastplates. The Soviets had also developed Manganese steel breast plates during WW2, and those were likely available to the Red Chinese.
The .30 Carbine was in part prefered by some to the Thompson because the .30 bullet would penetrate the heavy vests worn by Imperial Marine machinegun crews while the .45 would not. The Japanese helmet was also noted for stopping pistol bullets but not the .30 Carbine bullet.
Round nose FMJ bullets of all calibers of 8mm or less had a poor rep for stopping power, even the .303 MkVI and 7x57 174 gr round nose had little stopping power unless they struck bone. Through and through chest wounds seldom stopped a charging enemy if his blood was up.
During the 1905 war between Russia and Japan the Russians issued thousands of sets of body armor to officers.
The breastplate was of nickel steel and under this was a thick quilted tunic of many layers of silk. The Japanese bullets flattened or broke up on the steel and whatever got through was caught up in the silk.
There were numerous types of body armor available by the begining of WW2 but cost per unit prevented any significant use , other than air crew flak jackets, till late in the war.
Last edited by Rainbow Demon; December 19, 2012 at 04:49 AM.