Actually as far as records go, Red Sex Links are only third among brown egg layers with one having laid 346 eggs in a year. Number 2 is a Black Sex with 352 eggs in a year, but a Black Australorp actually holds the brown egg laying record with 364 eggs in a year, and another Australorp laid 354 eggs in a year (
http://www.livestockconservancy.org/index.php/heritage/internal/australorp). In fact many people still think that the 364 is the all-time egg record, but it was actually broken in 1979 by a caged White Leghorn that laid 371 white eggs in 364 days (
http://cafnr.missouri.edu/about/chicken.php). However as a general rule though, both Black and Red Sex Links will outlay Australorps. My Black and Red Sex Links consistently churned out more than 300 eggs per hen per year, although my Australorps had a longer laying life. You should be aware however that even though sex links use RIRs in breeding (Black Sex Links are RIR roo X BR hen, and Red Sex Links are RIR roo X silver gene hen), RIRs cannot match the lay rate of sex links which outlay either parent breed. In other words, keeping pure RIRs will not achieve you a sex link laying rate. It's one of the interesting quirks of hybridization. If a high lay rate is your main priority, I would suggest going with Black Sex Links which tend to have the largest eggs of all breeds and hybrids with double yolks not being uncommon.