While the collet bushing did help assure a tight lock up, there were/are problems with fingers breaking. Most of the breakage was/is the result of poor bushing fit to the slide, off spec heat treatment of the bushing (the fingers are springs) or off spec machining of the fingers.
Everyone has "heard" of broken collets, but how many actually break? I'm starting to liken the broken collet to the cracked Delta Elite: If ten frames crack, and the story is retold 1000 times; is that 10,000 cracked frames? Kuhnhausen's manual left me with the impression that collets either break or don't. If the slide is machined properly, and the dimensions are within proper tolerances, the collet will work fine. If something was wrong, it probably would have broken long before it was thirty years old. Solid bushings can break, too.
I've seen two. I was at the range (next to the shooter) when one broke a finger. We had a heck ofa time getting the pistol apart. The other one was brought into a buddy's gun shop while I was there for repair/replacement.
I've got collets on 2 series 70's, each with between 10,000 and 12,000 rounds through them.
I did have one that had a collet finger crack at about 8,000 rounds but that was due to poor machining of the collet finger itself. I still have the collet bushings and will continue to use them, after being inspected.
I have had to take a couple out that broke in use. Like you guys said you need a mallet to take the gun appart. For competition fine
for Defence I would pass. This Particular jam makes the gun totally unserviceable. In a sport with allabys (clearly spelled wrong)
it is fine. I suspect it does the gun and barrel no good to jam solid. I have seen probably 6 but as I have seen people would bring a gun to a gunsmith because it is broken.