OP, looking at tirerack, in 19in diameter, A/S+ only goes up to 275, A/S 3 goes up to 285.
Plenty of examples using 305 on 10in rim in this forum, but for the sake of knowledge, please do read and understand the below then decide based on your end goal.
http://www.tirerack.com/tires/tirete...jsp?techid=199
Then an example spec of a 305/30/19 below, pay attention to the "rim width range" and "measuring rim width"
http://www.tirerack.com/tires/tires....=yes&tab=Specs