Funny you should ask, I have not one but two crowns, and prefer a swivel stud. This is because it is lighter weight, less obtrusive particularly if I want to shoot the rifle naked or off bags, and still does everything I want it to do namely serve as a mounting point for a Harris style bipod or mount to the top of a tripod.
Here are some pics I have kicking around:
I start with a wood screw swivel stud which can be bought from the usual suspects for just a couple dollars.
Next I carefully unscrew the bottle. Go slowly until you hear a "hiss" then stop. Wait until the hissing stops, and then unscrew the bottle the rest of the way (it should be easy now as there is no pressure loading the threads)
Now you have clearance on both sides of the "tongue" under the bottle. Put masking tape tightly over it and mark the center carefully. (this is the most tedious step, usually takes me a while and I use calipers and double check everything to make sure it is all aligned perfectly)
Set the hole center with a punch so your drill point won't wander and then drill it slowly and carefully. Because you're cutting plastic, you may want to brass-off the tip of your drill bit so it doesn't feed too aggressively. I always measure the core of my screw very carefully and use a drill bit just a whisker larger diameter than that. You want the threads to have good bite, but remember that deformed plastic has to go somewhere and you don't want to crack anything.
Carefully thread in the screw. A tapered awl or even a hex key can be really useful here to help you hold the eyelet perfectly aligned as you thread it in. LEAVE THE MASKING TAPE AS YOU START THREADING. Only after the screw has some bite should you pull the masking tape off, as it can help stabilize that surface coating FX puts on their synthetic stocks.
And, finally, once it is started pull the masking tape and carefully thread it in. and make sure it is square. Don't torque it too hard and stress the threads and don't go too far because then you'll be made of regrets when you have to back it out to get it square.
I hope that helps explain my procedure to install a swivel stud. Obviously some people prefer rails, which is about the same procedure but a little more challenging to install. I've never been want for a rail on either of my Crowns though, so if you like the Harris style bipod you likely won't be either.
If you want to go with one of the Atlas style bipods you'll want either a rail or will want to pick up one of the stud-to-rail conversions so you can mount it. Something like
THIS. Different strokes for different folks.
I hope that helps mate!
