[2019] What's the best Swarm Defence Strat?

Yesterday I joined a really fun session with some Japanese dudes. They employed a very clever strat for handling swarms. The pair of them had this very well practiced. The Driller would make a path straight into a cavern wall, perhaps 15m long and then hollow out the end with a circular compartment.

As the waves bottlenecked at the entrance, the gunner would carve through them like a hot knife in butter and my Engineer's LMG would pickup the slack.

The Driller's bouncy secondary was used to comedic effect as well but with all the ragdoll bodies dematerializing amid the choas at the entrance, it was hard to guage it's effectiveness.

So, what's your gold★ strat?