All our No Drill-Tap scope mounts are precision CNC-milled and feature steel receiver nut, aircraft grade aluminum alloy picatinny rail. They are guaranteed to be rock solid and requires no permanent modifications to your rifles.
The following videos show results of our testing and how accurate these WWII military surplus rifles can be:
The first video is an accuracy comparison between Mauser K98K, Mosin Nagant M44 and Swiss K31, all equipped with our Gen 1 NDT mounts:
In the video you can see that I was having the vertical stringing issue with the K31. After reading Pierre St. Marie's accurizing article, I was able to tighten groups significantly:
1). Relieved stress points from the barrel by *lightly* sanding the stock and handguard and added two copper spacers in both barrel bands.
2). Adjusted the action and tang screws torque and tested fire until I found the best combination. While this method works well, I don't like the fact that I need to use thread locker because that means I need to re-apply it every time I disassemble/assemble my rifle. I think the purpose of adjusting the action screws torque is to free float the barrel. And this can be achieved by adjusting the thickness of the action shims. So that's probably what I will do next.
The result after the accurizing: