ORIGINAL: bigbulls

See the part with the arrow pointing to it? You unscrew the barrel band, pull the screw out, insert this part between the band, and replace the screw. The swivel attaches to this.

The rear studd you will have to drill into the stock but there is a section of thick plastic at the rear of the stock that extends a few inches from the butt plate. Measure two inches from the end of the stock and drill a hole for the longer studd to screw into.

The short screw is there if you would rather have the front studd screwed into the stock. It is shorter so it won't make contact with the barrel.