The forward hole is where the bolt attaches the peep to the safety. The slot interfaces with the tang on the safety to hold the peep in position and still allow a way to rotate the safety. In this example I roughed in the hole with a row of holes and then used a needle file to match the taper on the safety. This is rough, but I knew I was going to fill it with silver solder.
It's way too tall, but by having the peep bolt to the safety you could make several different height peeps for different loads. I'll work up the load I want to use and then just make the peep the height I need. I also want to cut down the front sight post and bring it and the peep as close to the barrel as I can. The peep also needs to be a little wider around the sight hole.
