Rory Burns was one of three Surrey half-centurions as the defending champions took a first-innings lead against visitors Somerset on day two at the Kia Oval. The Brown Caps skipper struck 10 boundaries in a fluent 76, sharing a first-wicket stand of 129 with fellow former England opener Dominic Sibley (53), who passed 50 for the fifth time in six innings this season. England wicketkeeper Jamie Smith was the third to reach his half-ton with 58 as the hosts closed on 321-7 at stumps. Somerset's bowlers recovered from a morning where they bowled too full a length, skipper Lewis Gregory leading the way with 3-46, including a double strike with the second new ball, as four wickets fell in the final session.