The long one is a modern rifle bullet, a good measurement would identify the caliber. The other one if copper jacketed looks like a .45 ACP (automatic Colt pistol) slug that ran into a wall. It is modern also although the .45 ACP came out in 1911. I'm thinking all the Brooklyn parks have been pounded for years and I hope you have the required NYC permit to hunt parks. Just a hint, any bullet with a copper jacket is a fairly modern slug. Also welcome to the site, hope you find some great things with your new 600! Some cool stuff comes out of Brooklyn, I have a civil war era eagle breast plate that was dug in Brooklyn in a latrine pit at an old encampment site.