Your barrel will only fit a Detonics slide, and chances are it will only fit an older Detonics slide as they changed the barrel diameter after serial number I6000 or so. I would guess that your gun is under serial number 3659? If so you not only have a cut/welded slide but probably the frame also. I had a slide that would fit your gun but just recently sold it. They are hard to find as is any old Detonics parts. The only other option would be to hopefully find a complete top end and have it fitted. I have seen some top-ends on ebay and they normally go for VERY high $$$. I would think that if you shoot allot at the range try using powder puff loads for most of it and then use regular loads for real practice. Watch the slide for cracks in the weld areas.
Good luck!
L8r
Conley