If your playing a 500 point game you wont see many AV 14's. Or if you do, maybe on one facing. Thats what the sentinels are for, they hit side armor.
IF your are worried about that kind of metal, do as Iraqiel suggested and run melta vets in a chimera. Mossy is spot on as well, autocannons are an IG infantrymans best friend, along with a flamer or grenade launcher.
As far as your vets right now, no snipers. Vets, in my opinion, should stay mobile. Keep heavy weapons off and give them either melta or plasma. Otherwise I like. Maybe add a commissar if you could spare the points, the infintry blob could use the ld9 and stubborn.