I’ve been using and recommending http://www.bulletproofme.com for a while now. They sell all manner of “generic” manufactured ceramic plates. The prices are excellent and the selection is second to none. Their level IV LW plates are rated to 30-06 AP. I’m happy.

One question to the SMEs in the room; as long as you’re not rough with them and don’t expose them to water and saturate them with sweat, what breaks down and necessitates a 5 year replacement timeframe?