Builth Wells remain at the top of Division Two West after a 34-14 win at Gorseinon.
Dan Davies, Chris Davies, Matthew Lewis, Gethin Davies and George Jenkins scored the five tries that earned the Bulls a bonus point.
Holding games in hands over Builth Wells, Loughor and Bridgend Athletic also picked up bonus point victories away at BP Llandarcy (16-37) and Waunarlwydd (15-44) respectively.
Pontyberem remain top of Division Three West after sneaking past Laugharne 6-3 in a game that saw no tries scored.
Quite the opposite in Llanelli, as Tumble fell to a 76-0 defeat against a Cardigan side that crossed 11 times.
Division Three South West leaders Tondu edged out Natyffyllon 20-14, with closest rivals Aberavon Quins similarly squeaking home 21-16 against Skewen.
Llandeilo thrashed Burry Port 48-3, notching eight tries in the process, to extend their lead at the top of Four West.
There was also a bonus point for Cwmgors, who broke their duck at the bottom of the table in a 19-12 defeat to Hendy.
Division Four South West leaders Resolven remain unbeaten after their 29-20 win over Neath Athletic.
Cefneithin beat Llangwm 64-3 at the summit of Division Five West, with second place Furnace United keeping up the pace through a 25-10 win over St Clears.
With Alltwen not playing, Abercrave used their game in hand to cement themselves at the top of the Division Five South West table through a 56-5 victory at Bynea.
Penlan won 17-11 at Nantgaredig at the top of Division Six West.
Wales reached their first semi-final since 2013 in the opening round of this season's HSBC World Rugby Sevens Series in Dubai. WRU TV's Graeme Gillespie recaps on what proved to be an eventful tournament
Wales and Ospreys back row James King, who came through the North Wales age grade system, nominated North Wales Regional Community Rugby Manager Marc Roberts, in the WRU's 'Diolch' initiative where squad players thanked those who played a part in their rise to the top.
Beating Merthyr has boosted Carmarthen Quins hopes of reaching a top eight spot in the Principality Premiership. Quins captain Haydn Pugh is delighted with his team's progress and is determined that everyone from the Under 6s through to the senior team, enjoys the ride.
When the Wales squad were asked to nominate individuals who played a big part in their early playing days, Wales and Dragons full back and wing Hallam Amos thought of his former Monmouth School rugby coach John Bevan.
Sam Cross and Luke Treharne have been named as co-captains of the Wales Sevens side as head coach Gareth Williams names his 12-man squad to play in the first leg of the HSBC World Series in Dubai next weekend.
Bedwas head coach Steve Law and players Nicky Griffiths and Alun Rees extol the virtues of the close knit club as they prepare to host third place RGC 1404 - who are one place head of them on the Principality Premiership points table - on Saturday.
Many of the Wales squad have said Diolch (thank you) to someone who played an important part in their early playing days by nominating them to be invited to the Wales v South Africa match. One person, Gowerton Comprehensive geography teacher Mr Dean Mason was nominated by two of his former pupils, Dan Biggar and Sam Davies.
The second WRU disability rugby pilot has been delivered, this time in Caerphilly schools, culminating in a festival at the Caerphilly Centre of Sporting Excellence, Ystrad Mynach tomorrow. Plans are in place to set up a Disability Rugby Club in Newbridge to provide long-term playing opportunities.
WRU TV: Hear from inside the Wales camp as Neil Jenkins discusses this weekend's clash with South Africa and how the squad are looking to put in a strong performance to round of the 2016 Under Armour Series