I used to do a lot of beads. Sounds like you've already drilled and tapped the rib/barrel for the bead. You can probably test-screw it into the hole and see how you like it.
Does the hole you D&T'd go all the way into the bore? Youll have to carfully cut off the part of the beads threaded shaft until its flush. Do this with the bead out of the barrel. Once you have the bead threaded in use a brake hone or careful hand polishing with a piece of emery cloth or fine sand paper to break any edges in the bore. Last, pull the bead out and put some locktite (Blue will work well) on the treads and screw it in. Wipe any excess locktite the leaked into the bore out.
Once you have the gun out to the range, check the following out. Does the gun shoot high? Often a shorter barrel will require using a bead base to get the point of impact down.
Does it shoot correctly in windage? Sometimes those little matted lines arent centered on the bore and your POI will be off. Never happened to me, of course (cough, cough). Luckily, thats an easier fix. These beads are usually longer than they are wide, and can be gently (gently) turned to correct. If thats still not enough, you can bend the bead (very gently) by using a brass punch and a light hammer to tap it over. Dont forget those capsules are very fragile. After you install it wait a day and check for brightness to see if the capsule survived.
