Jking: I agree about the rather solid gearing on the KO backs. I measured the thickness of the two films with my dial caliper and found that each film is very close at 0.005 in. even though the flexibility seems to belie this. The paper however was 0.003 on the EFKE and 0.004 on the TX rather close and almost insignificant as compared to the results. It may be just enough difference to cause my observed problems due to the difference in buildup as the leader wraps onto the take-up reel.

The EFKE film seems to work well in my C330f!?

David: the Mamiya C330f has such a device for metering but the KO does not. It seems to be set for certain film thickness and as jking mentioned, always cranks a given number of turns set by the frame number. In fact the KO is the only camera Ive seen in which the film never contacts rollers et c. during advancement. The film moves directly from supply to take-up and only contacts the focal plane framing as the shutter release is pressed (David, I know you know all bout this, but some readers, especially those new to film and MF may not). This is the first experience Ive had with poor operation and I will get to the bottom of it. I think I will take your advice and wind on a little extra paper on loading maybe a couple of reel rotations. If we are correct, this will modify the registration and could correct the problem.