BR Warmup Map/Gametype

In Halo 3, there was a map and game type floating around which was fantastic for warming up with the BR. Essentially it was a round based game type where you battled an opponent in a smallish rectangle with leach enabled so that the most consistent player, generally over several clips, eventually killed the other.

I am wondering if there are any similar game types that people have played with would serve a similar purpose. As far as I understand leach is no longer available in Halo 4 but surely someone creative has come up with something else brilliant. Given that matchmaking is dominated by power weapons I usually find it takes a lot longer before I feel ‘warmed up’, and I’m sure I’m not the only one.

I don’t know about a square map, but Octagon has always been the warm-up map for Halo. I don’t have an actual link, but look it up on Youtube or something. It’s just a small map with limited spawns, and people can just spawn with BR (or any other precision weapon, I guess), and sometimes a Sniper. It gets crazy with enough people!