RE: mossburg 500 help
I've used a Mossberg 500 20ga the last 5 or 6 years. I didn't get real good patterns until I went to a Hastings® Super Full extended Choke Tube, non-ported. I use a horded stash of Remington® 3" Mag 1¼oz of #6 Hevi•Shot®. With this combo I put 29 pellets into a 3" circle @ 40yds. I'm confident of my gun & load to a full 40yds. That's asking a lot of a 20ga but my choke & ammo combo will do it. I bet if you get a Swarm™ choke & shoot with the Federal® loads you described you'll have an awesome combination.