On the stock rail you have to pull out the barrel index pin, the spring loaded pin that holds in the twist lock barrels.
On the detent issue Crystal has been great and it is an issue on CP's end. The tolerances on the detents are pretty tight and they just had a bad run. However I did get the body working with a Check-It detent. The stock setup wont work, it doesnt go in far enough, but the Check-It has a separate body and cap. I put a small washer in the cap so it doensnt screw down on the body quite as far. The CP detents certainly look better as the Check-It is a pretty basic flat cap but it will work with a little tweaking. I'll just swap out for a new CP once I get my replacements.
Bad detents aside I really dig the new body.