There used to be a source for slides for this conversion that matched up the dust covers to a government frame...I think they were made by Caspian but I don't remember exactly...either Brownells or Caspian.
They will work in 45acp, but the throw is shorter so I don't know if that will work for a 400 Cor-Bon...if you can find a slide.
Also check if you have a ramped or bushing-less barrel.
A lot of guys are shooting 40sw 1911s.
