Weapon of choice for horde killing?

What is your favourite setup for horde killing?

I'm new to the game and I reached the point where deacon asks iron mike help to blow the cave where freaks be lying, so my choice of weapons isn't all that great.

Apart from molotov cocks I really like the MWS and the SMP9, for special weapons I like a lot the MG45 that I stole from heavy rippers (I'm not at level 3 at hot springs so I can't buy it yet, hell I'm not at level 3 nowhere XD)

I don't have traps or napalm yet so my strategy is to bait them into following me on the bike, killing the closer one as the farthest quickly lose interest.

Worked pretty well for 100 +- gruops but I doub't it'll work as good on the sawmill gigantic horde.