My Conn 88H (closed wrap) fits nicely with room to spare, so open wrap horns shouldn't have a problem fitting inside (you might need to push the tuning slides in, though)

This case seemed to be a great fit for my horn, and it comes with its own straps to carry it

but I think the smaller horns get deprived of a perfect fit

Nice fit for my King 4B

They really like the look and the way their instruments fit