Hey, I don't really know how to edit the wiki so I figured I'd just point it out here.
Right now the only gun in the Magnus line noted to have a blast radius is the Iron Slug, this is misleading as the Callahan, and the Mega Magnus both have the ability to hit multiple monsters on impact as well. Although it appears to be easier to do this with the mega magnus than the callahan, suggesting the callahan might have a reduced blast? I can't recall if the Magnus has one, but will be making another one soon for a friend and will be able to check on that.
I don't have an iron slug so I can't test if there is a difference in the blast, but I do feel it's really misleading to say that the Iron Slug has one while leaving it off on the other guns.
All guns have small splash damage, really. Just wiki editors aren't terribly consistent.