Killing RR alfalfa

Baled fourth cutting alfalfa about a week ago so I'm starting to get a couple inches of regrowth. I have decided I want to kill this field of alfalfa and plant pure grass. The field is small with a lot of shaded edges and the alfalfa doesn't grow well or dry drown worth a darn. It just now occurred to me that this is RR alfalfa and I can't just burn it down with roundup and drill in grass right away. I know dicamba and 2,4d will kill the alfalfa but a rate high enough to kill it would prevent me from planting grass for at least a month. Is there anything I could spray and be able to plant grass in the next two weeks?

Hayden

Killing RR alfalfa