Hi,
I've used my version made by L&R (they don't make it anymore) a lot. On a round-faced lock, as long as you make sure the jaws are not digging into the raised area on the plate under the cock, it works just great even on Kibler locks. When done carefully, it won't mar a blued or browned finish on the lock except sometimes directly under the cock. However, the limiting factor is the amount of space between the cock and plate. If the cock fits very close to the plate, you may have trouble slipping the jaws under the cock. That is why I had to thin the jaws on the L&R tool. They left the jaws too thick. Robert's machined jaws look to be far better than the cast ones on the L&R and should work very well. When removing a flint cock, I first try the my removal tool. If the cock fit is too close to the plate, I use a punch and hammer to tap the tumbler out. If you do that and suspend the lock plate between jaws of a vise, put a rag, towel, or carpet remnant between the jaws to catch the tumbler if it falls. I have a piece of carpet that is a little stiff and holds itself nicely between the vise jaws.
dave
dave