Balcombe efforts in vain
Pace bowler David Balcombe took a career-best eight for 71 but Hampshire struggled to make the most of his achievement against Gloucestershire.
Balcombe, who spent much of last season on loan with Kent, staked an early-season claim for a regular place in the Hampshire bowling line-up.
But the hosts were held up by another man claiming a personal-best performance in the shape of Gloucestershire opening batsman Chris Dent who made a diligent 114 spread over 94 overs, and the south coast team then limped to 182 for seven in reply at stumps.
Dent's century was only his second in 30 first-class matches and comfortably beat the 100 he made against Surrey in 2010.
Gloucestershire, who were asked to bat first on a wicket helping the bowlers, recovered from 87 for four to reach a respectable 314 thanks in the main to Dent and Ian Cockbain.
Dent and Cockbain put on 133 for the fifth wicket with Cockbain striking 11 fours in his 64.
Ed Young later helped Dent add a further 80 for the seventh wicket as conditions eased in the bright sunshine before Balcombe removed them both to catches at the wicket by Michael Bates.
Bates took five catches as Balcombe ran through the Gloucestershire tail, with Dent eighth out after facing 270 balls and hitting 16 boundaries.
Hampshire did not help their own cause, conceding 43 extras including 20 no-balls and nine byes.
They were soon in trouble when they responded by losing their new captain Jimmy Adams and Michael Carberry with 24 on the board and then Liam Dawson at 81.
Medium-pacer Will Gidman dismissed Adams, Sean Ervine and Bates in a tenacious spell while Carberry was run out by a throw from Dan Housego.
With Ian Saxelby claiming the wickets of Dawson and James Vince cheaply, it was as well for Hampshire that former Australia batsman Simon Katich held firm while wickets tumbled around him.
Katich, at the start of his latest spell with the county, reached 74 without concern until he guided Saxelby to David Payne to leave Hampshire reeling at 160 for seven.
At the close Hampshire were still 132 behind, and with Gidman and fellow medium-pace bowler Saxelby each having played prominent parts in Hampshire's tribulations.
Gidman finished the day with figures of three for 43 and Saxelby had taken three for 37, leaving the match evenly poised.