Re: lapping alloy rings
The only way to truely know if the rings are parallel and true, is to use a kit to measure them. I use Badger, Seekins, IOR, Leupold, and a few others that I'm missing. Depending on the brand and quality, such as Badger vs Leupold, they have all required lapping and were not true. Some people say not to lap aluminum rings because you can weaken the strength. To me, it is fine, just be cautious how much material you are taking off and check it often for alignment.