First I ground the threads off the bolt to form the shoulder and then threaded about 5/8" of the neck of the bolt with a 22mm die. I drilled a ½" hole, then enlarged it a tad with a emery cloth wrapped around a 3/8" rod chucked up in a drill press until it fit snugly over the end of the barrel. I also used emery cloth to smooth the outside of the barrel. I then drilled and tapped a hole in the shoulder for a 10-32 allen screw.

Below is a drawing of the sanding rod. I used it a lot. As the sandpaper wears out, I tear off small strips.

CAUTION: Take your time and make certain the 1/2" hole is drilled straight and centered, and keep the die aligned correctly. Otherwise you will end up with the break misaligned with the barrel, which could result in a bullet striking the front of the break and causing serious injury to yourself, or someone near you.

I wrapped the cleaning rod with masking tape in two places to give it a snug fit in the barrel, and used it to check the alignment of the break in relation to the muzzle.
The die is a large one and I didn't have the proper size handle, so I used a pipe wrench. This makes it a bit tougher to keep it straight, but I was slow and methodical and got good results.

When making the threaded hole in the shoulder of the break, mark the adapter and slide it over the barrel and position it where you want it. I slid mine a bit towards the front so it would give the break more stability, and I didn't have to inlet the adapter to accept the retaining pin. Drill the proper sized hole for the tap you are using. Drill through the adapter just enough to mark the barrel. I drilled the hole in the barrel with the same bit I used in the adapter, so I had to grind the threads off the allen screw on the portion that will seat in the hole. You could use a larger bit for the second hole if you want.

Use a longer allen screw then needed so you can grind it to length. When tightly seated, you want it as long as it can be without interfering with the break screwing on. This will insure it being held in place, even if it works loose.

This will sound obvious, but be careful not to drill the allen screw seat hole too far into the barrel. It does not have to be all that deep, so long as you be certain to make the tip of the allen screw slightly pointed, like the drill bit tip.

If you followed the above steps correctly you should have some thing that looks similar to the pictures above.

Once you have blued the barrel tip and the adapter, screw on the muzzle break and check for alignment and fit. Mine was a bit loose on the threads, so I wrapped the adapter threads with plumber's Teflon tape until I got a nice, tight fit. The final product should look similar to below.