zxcvbob, I had the exact same base pin problem with my Gaucho in .45 Colt. Taurus replaced it but I had the same problem after shooting a few cylinders through it. I found that the Belt Mountain standard pin that's made to fit SAAs and clones would fit, I just had to shorten it by about 3/16" so it doesn't interfere with the transfer bar. That pin seems to be properly hardened as my problem is solved, and it's been a great gun since. The Belt Mountain pin wasn't very expensive, and only took a few minutes with the Dremel to make it work.
Link to Belt Mountain base pin at MidwayUSA
I really like the Gaucho and Taurus in general, hopefully they've got the little issues ironed out. I bought mine pretty early on, in fact I think it was one of the first ones my local dealer received.