Cork Constitution were in second place at the start of the day but were well beaten, 34-13 by Garryowen in Dooradoyle.
Buccaneers moved into the top four after beating Lansdowne 8-3 while UL Bohemians continie to hug the bottom rungs of the table after they were beaten 23-19 by UCD in Thomond Park.
After losing their two opening games, Shannon continue their upwardly mobile surge although being put to the pin of their collar to get out of Oak Park with a 18-10 victory over a home side Co Carlow who will rue the five missed penalties. The sides were tied 10 points apiece at half time before captain David Quinlan put Shannon back in front with a try and then Andrew Thompson extended the lead with his second penalty of the afternoon. Carlow had two further penalty chances to snatch a bonus point and they came within inches of a last gasp try when Ian Dwyer was just beaten to the touchdown from a chip-through.