Gunfire Reborn

First off leap is your "primary" skill. (LB on console / E on PC). Load up a game on normal and the easiest way to boost this is to find an an elite Beetle in an act1 vault. These guys continually spawn 4-7 beetles at a time. once you kill the other enemies in the vault just kite around the elite until he spawns 5+ enemies and then leap. When I was doing this alot of times he would spawn faster than my leap would come back. There are a few other points in act1 that have 5+ enemies that spawn, however this is the guaranteed way. This doesn't require you to get far into the game, so it can be boosted pretty early. The Elite Vaults look like a "horse" head. I did have issues with tracking of this achievement. it seems to update often once the "run" is over. When I did this I got about 75% in 10-15 mins.

There isn't alot of good enemies to do this to in Act2 as they have alot of health. Some enemies in Act3 would be the lanterns, monks spawn lanterns continually, and firecrabs (no way to respawn these though).

Good luck and happy jumping!

The tracking is a little delayed for this achievement, for me at least. It usually updates a short time after ending the run.

The best place I found to grind this out is Act 3, the monks that summon the pack of 3 exploding lantern guys. Just kite the lantern monsters around until there's 6 of them close enough together to kick them(lb by default), they have very little health and will die from one kick with no dmg upgrades. If you can find 2-3 monks together even better and quicker.