Federal Tactical is some of the best and most accurate 00 buck availible. There are different variations, but I use the 132 which is 2 3/4 low-recoil, 9 pellet 00 buckshot. Low recoil buckshot loads offer a huge advantage for HD work as they have significantly less recoil and the reduced velocity has a negligible effect on terminal ballistics, but it does allow for much faster follow up shots. In addition to the Federal Tactical 00 buck, I used both Remington and Winchester 000 buckshot. In my guns, the Winchester 000 buck is more accurate and patterns tighter, but Remington is a close second. I have also used Hornady TAP 00 buckshot which is excellent ammunition as well, though IMO nothing beats Federal Tactical 00 buck. I have around 1k of Wincehster 000 buckshot for SHTF use, as I prefer 000 buck for this application especially a full power shell.
I have found Remington "reduced recoil" 1oz slugs to be the most accurate slugs I have fired out of my gun. Federal Hydrashok slugs are also very accurate out of my gun, but not quite as accurate as the Remington reduced recoil. I also shoot both Federal/Winchester 1oz slugs which come in the value packs from Walmart. These are decent/accurate slugs for the money and are excellent to stockpile. Bar-none, the Remington's were the most accurate slugs I have shot in my guns.