My Ciener kit functioned perfectly for the first 500 rounds, which surprises me as I had heard that it may take some time for the unit to "break in". My problems started later. Now I'm getting failures to fire on 5 out of 10. If I re-thumb the hammer back on the round that didn't fire, it will then fire. I followed all Ciener recommendations (Win Super-X hi vel, constant cleaning) but the problem persists. Guy at the range suggested I replace the recoil spring, his theory being that it has lost some strength and is not closing the slide completely, thereby causing light pin strikes, and that the first strike lighly impacted the primer but fully shut the slide and the re-strike then fully contacts the primer. Does this seem right? If it is, can I simply stretch the spring out myself when this problem occurs? How can you judge the amount to "re-tension" the spring? BTW, Ciener has been great with providing advice and willing to do warranty work on the unit, but want me to ship my full-size frame along with the conversion unit back to them for testing, which I'm reluctant to do.