I have no doubt things were torqued per spec. However, just because it's torqued doesn't mean it fits correctly.
To understand these Talley LW's, people need to realize they are an aluminum extrusion. That's not good or bad..it's just what they are. The extruding process imparts an enormous amount of stress into the material, which remains in the product after it's finished. When a highly stressed piece of extruded aluminum is mated to another part, it's imperitive that the fit between the parts be such that no additional stress in put on the part. When an extruded piece flexes in an attempt to conform to the shape it's being mounted on, the additional stress on a piece that already has a lot of stress in it can cause them to fail.
In the picture, the stress crack is vertical...right up through the mounting screw area. The pic clearly shows that the bottom of the mount in no way conforms to the shape of the receiver. And additional stress is put on the rings when the tops are screwed down since the parting line area of the Talley LW's often rolls inward.
I've written and showed pics dozens of times on how to get ahead of this, not only with the Talleys but other setups.
The last few sets I got have some subtle changes to them, including a longitudinal relief cut on the underside of the base...likely in an attempt to get them to conform better to the receiver shape. I think all this cut does is to remove strength in an area that's already highly stressed....thereby making a bad fitting situation worse. In a decent fitting situation, it might help. It would be interesting to see if that set of rings show that relief cut.
Rails and other mounting systems can be more forgiving...which people mistake as 'better'. when it comes to issues like this.
While I love the Talley LW's, they're certainly not for those that don't want to take it further and have a stress free, light weight setup. They bolt on rails and think they're great. But the stress is still there..it's just under the radar.
This won't exactly endear me to the masses but there you have it.
Good shootin'.
-Al