@unclemoak, if you want, I can send you (for free) 3 original Stiller Mk13 scope bases to mess around with on your receivers. The Stiller Mk13 receivers are fully round, so they should fit the profile of your 2 LMT receivers perfectly. However since your receivers have a Remington 700 long action screw hole pattern and the scope base has the Stiller Mk13 screw hole pattern, some modification on the 2 rear scope base screw holes is needed (this is very easy to do).
Here's a few photos of the 3 Stiller Mk13 scope bases, all 3 bases are new in bag and include the original mounting screws. These bases also have 20 MOA of elevation added, which is a desirable characteristic that you're probably also looking for.
Here's one of the Stiller Mk13 scope bases on an original Remington M24 long action receiver (it's not a fully round receiver, but that doesn't matter for the screw hole comparison). I used this receiver as example to show the Stiller base screw hole pattern in comparison to the screw hole pattern on the Remington long action receiver (since that's the screw hole pattern on your 2 receivers). This is what the Stiller scope bases will look like when you out them on your receivers.
Notice that the 2 front screw holes in the long action receiver line up perfectly with the 2 front screw holes in the Stiller scope base. No modification needed here.
However, the 2 screw holes at the other end of the Stiller scope base don't line up with the 2 rear receiver screw holes. The rearmost screw hole on the Stiller base is very close to lining up with the rearmost screw hole on the Remington receiver. You could just open up this rear screw hole in the Stiller base a little bit, and then it should line up with the corresponding screw hole in the Remington receiver. So, this is a very simple fix for this scope base screw hole. Or you could plug the rearmost screw hole in the scope base, and then drill a new rear screw hole. Do this if you don't want to open up the rearmost screw hole in the base and then have an oval-shaped hole instead of a nice round hole. So, you have 2 options for this one.
The screw holes that don't line up at all are the rear receiver and scope base holes in the rear right by the receiver's open port (the one in front of the rear-most screw holes). The receiver and base screw holes don't line up at all, so this needs to be modified. The easiest way to do this is to measure the distance from the rearmost screw hole in the receiver to the other rear screw hole in the receiver (they aren't very far apart). Then, measure this same distance on the scope base starting at the rearmost screw hole on the base and measuring towards the front of the scope base. Mark the location for where the other rear screw hole should be in the scope base, and then drill it out. You can then plug the hole that doesn't line up at all, and then refinish the scope base.
Here's a view of the 2 front screw holes, notice that the holes in the receiver and the holes in the scope base line up perfectly:
Here's a view of the 2 rear screw holes, notice that the holes in the receiver and the holes in the scope base don't line up. The rearmost screw hole in the scope base (next to the "07" marking) is close to lining up with the rearmost receiver screw hole. As you can see, the other rear screw hole in the scope base (the left screw hole in the photo) doesn't line up with the corresponding screw hole in the receiver, so a new hole needs to be drilled into the scope base.
You can see in the photos that yhere are 2 tiny holes in the scope base, these were probably added to index the scope base or hold it in place when it was being made. I've seen similar holes that were for the same purpose in Crane made Mk13 scope bases. You can either leave these holes as is, or plug them with a pin before refinishing the scope base.
Your shop is known for it's great work, so you should be able to make very quick work with the modifications for the rear screw holes in the scope base. And since it's a fully round scope base, it will fit onto your fully round receivers perfectly! I figure that drilling and plugging a few holes is a lot easier than trying to mill a new fully round scope base. And since these 3 scopes bases are free, it's also a lot cheaper than spending hundreds of dollars on new scope bases that may or may not work for your receivers. Even though you only have 2 receivers, I can send you 3 scope bases so that you have one to practice on or use as a replacement if something goes wrong when you're modifying the screw holes in the scope base. I can send you more than 3 bases if you need a few more, but I'm assuming that 3 is probably good.
@unclemoak, please shoot me a message with your shipping address if you want these scope bases and I'll send them to you. Please let me know if you have any questions about these Stiller Mk13 scope bases, and I'll do my best to provide any answers. Hopefully they're what you need for your rifle builds!
