Not sure I can give an exact answer. The Ideal stock/holster was made in at least a couple of sizes. Mostly they are for the 4.75"/120mm barrel length, but I have seen pictures of one for the 6"/150mm barrel. Also there were some slight variations in the hardware from early to late production, but nothing that would make much difference in the dimensions (I think). I don't have any info on the longer version but here is what I measured on my short version.
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