There's ways - but it depends on the situation, depends on what exactly is on the bench.
For instance, 11/16" equals 0.6875"
If you have an 11/16"x20tpi hole and a Colt barrel with a slightly larger diameter 20tpi stub, and you have the right skill set and a proper lathe, you can get them together without tremendous metal removal.
There's other issues to consider, but there's a thumbnail look at part of the problem for you.

There are reasons why custom revolver work costs whatever it costs. It takes knowledge and experience and skill as well as tooling *and it takes time* to get these things together - and not all vendors are equally qualified to do the work.

If you have a gunsmith who can make it happen, get with them first and then go forth with your sourcing of whatever you need for the project.

Consider that a revolver barrel can be made from a bare barrel blank, and can be cut and profiled and threaded and populated with sights and ejector rod housing etc *all from scratch*. That happens every day.