@Fireflyfishing , your pictures make me think that maybe the mag well in the krg stock is longer than in a Tikka stock. Maybe try putting some built up layers of tape or some epoxy on the rear of the mag to see if that helps. If it doesn't work you could sand the epoxy off.
Also, if you decide to go with a different mag I might be open to buying one from you.
Since these are printed, it would seem easy enough for them to tweak the file and build up that area of the mag a bit. They'd probably need their own Echo to do this (not sure how popular it is either, so may not be a problem that they see worth solving).