I personally wouldn't use ammo not specifically designed for the firearm in question. I have read reports here of vintage revolvers and pistols being irrevocably damaged by using +P loads. Cracked frames being the most common incident. Consider if blowing apart your not-easy-to-come-by 4566 is worth a little extra pow in your shots. I would suggest a S&W M&P2 in 45ACP if you're going to follow this. At least this model is readily replaceable.