My understanding when I spoke to Dick @ McMillan was that it's basically a remington pattern with some variances due to the nesika action. I was originally just going to order a remington pattern and Dick said there were enough variances that it was better to order specifically for the Nesika. Other than the round vs. square tang mine was a perfect fit. I think the variances are primarily around the loading port and as was mentioned around the depth. Since the edge is painted anyway, it will be a really minor fix when the tang in bedded.
