Popere, Think I will cause a stir here, forget the 3" shell! Take a AA in 23/4", Win 209 Primer, 34grs. Win 540 powder or HS6, Win F114 wad and 11/4 of #4 or #5 platted shot, PERFECT turkey load. Velocity is right at 1220 ft/sec. Won't leave a bruise either. I can load 25 for $3.75. I am shooting this out of a Win 1300 with a full choke. Not extra or super or turkey full, just full. The best shell I have ever shot and I have shot most of them. I even played with the duplex loads for a while, this is better.
As for a vest I have an old H.S. vest, love it. All my stuff has a pocket inside so it doesn't bang around. Have fun, shoot a lot of paper targets and play with chokes and shells and see what works best with your gun.
Gselkhunter