if you aren't sending very hot loads down the pipe it should be safe. most revolver, even older ones, can handle a few squibs with little issue even with a visible shadow. the problem comes from a combination of not knowing the history of that barrel, and examining it for cracks that the bulge has precipitated, which is where it's a serious safety concern. cracks from bulges (since bulges are from over-pressure) can fail very suddenly rather than progressively like you would assume.
the proper fix is either a new barrel, a fill and liner installation, or the preferred way which is a mandrel and hammering out the bulge, which is very difficult to do by hand (i use a power hammer machine). fill and liner will not last, trust me on that, i've done them and they are good for a few thousand rounds then a re-line is needed. a new barrel or hammering out the bulge might be cost prohibitive, hammering takes hours and hours of shop time.