Here's an interesting possibility???

Previous listing on EBay:

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The listing also includes a post of the installation instructions which indicates that a Weaver N2 (low position) or N3 (high position) mount should be used for Krags.

The N3 mount, shown below, has a hole spacing pattern that doesn't seem to match, however, various other Weaver N-Type mounts that I've seen appear to have wider hole spacing like the N4???

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