Each year about Christmas time I take the last years worth of catalogs I have received in the mail and bundle them up, sometimes I soak them in water sometimes I don't have the patience and shoot them dry. This year is was dry. After reading the .45 ACp Vs. .223 Rem thread I deceided to do my own totally unscientific test of the two calibers. I fired 2 50 grain HP .223 bullets, 1 60 grain Nosler partition .223 and 1 .45 230 grain HP bullet at the stack.
Conclusion: Being shot by any of them would suck big time. The HP penetrated maybe 4" into the dry paper and left nothing but shrapnel, the Nosler Part., penetraded a little deeper and looked like an abused Noler Partition weighing 44.5 grains with the bullet from the partition back intact (bulged and abused but intact), the .45 penetrated the least but made a nice hole and flattened out.
Standing by my conclusion that to be shot by either would be bad news. your test results may vary.