I have a couple of the Kimber kits mounted on E series 1911’s that have functioned perfectly so far. Those two 1911’s have fired a lot more.22’s than .45’s. However, they do very well with the .45’s.
I had a Kimber Rimfire Target Conversion Kit on a Kimber Stainless Gold Match frame and it failed to function more often than not so I sent it to Kimber for repair. It came back with a warranty invoice reading, "Replaced small parts." Heck, the whole kit is a small part! Anyway, it didn't work any better.
The second time back, I sent it on my frame in case it might be the cause of the problems. They said they replaced the mainspring housing on my frame and it still didn't work very often - and I was using their recommended ammo, CCI MiniMags.
The third time, again on my frame, it came back with an invoice stating that they could not duplicate the problem but it still didn't function right so I asked for an exchange. They agreed so I put a small mark in the interior of the slide and sent it back. A new kit was sent to me and I went to my club to try it out.
I shot 100 CCI MiniMags through it and out of those 100 rounds, I had 74 that failed to feed, failed to fire, failed to extract or failed to eject! It doesn't take a mathematics expert to see that amounts to a
74% failure rate. I fortunately was able to return the kit to the place where I bought the initial one, MidwayUSA, for credit and bought the Advantage Arms kit, which has been flawless.
After that customer service experience with Kimber, I replaced all my Kimber 1911s with Smith & Wessons. I had one occasion to return one of my PC 1911s for a suspected problem and received a call from the actual gunsmith working on it explaining what he would do to it and why. THAT's good service.
It turned out that I wasn't alone in having problems with a Kimber conversion kit. A few months after my episode with their service, two fellow club members showed up at our 25-yard range to try out their new Kimber kits on their 1911 frames. I watched them struggle with the same problems I did.
Ed