Over the last year or so I have been trying to get an Uberti Pocket Navy and 49 Pocket to behave. Both guns are new and were experiencing the same problem--hammer blowback. Both would do this even when simply snapping a cap! Was much worse when actually firing a load. Along with the blowback came the fired caps down in the hammer cut out of the frame. This was frustrating to say the least as you got one shot then a tie-up. I had done all the usual recommendations--hammer face was polished, Slix Shot nipples, Rem. #10 caps, action clean up, etc. I suspected the mainspring was weak and ordered two new ones. They were no different than the originals. So I cut one of the new springs roughly in half and mounted it under the original mainspring, in other words 1 1/2 springs. Things inproved slightly so I believed I was on the right track. I moved on to other projects and the Pockets were put on the back burner--but it kept bugging me. So last week I took a much stronger stock Colt SAA mainspring and fitted it to the Pocket Navy. It only took a little trimming at each end and it slipped right in. Hammer pull was heavier of course but not objectionable and trigger pull not too bad. Went to the range today--beautiful weather!--and had much better results. Fired the Pocket Navy 25 times with the usual load which is 15 grs 3F Olde Enysford, .375 round ball, lube on top of ball, Rem#10 caps. Out of the 25 rounds, 23 1/2 went off smoothly without any problems. Round #20 the hammer came back slightly(that's the 1/2) and round #22 had the only partial blowback and resultant cap suck. I suspected the hammer face, being quite dirty at that point may have led to the glitch as I hadn't cleaned it. The remaining 3 rounds went off with no issues.
So, the stronger mainspring appears to have worked. I can live with the improvement. Over the last few years I have read nothing but complaints about the problems people were experiencing with these Uberti Pocket models. I had several of these guns 20 years ago and did not have these same issues. I can only assume that Uberti is now using a less powerful mainspring for the Pockets. So now I get to try this out on the 49 Pocket in a couple of weeks and hope for the same results.