insert the T-nut and mark it flush with the outer bottom side of the stock. Once both of the T-nuts are marked to the edge of the outer bottom of the stock, carefully grind or file them to fit flush to the with the bottom, the swivel must fit tightly against the stock without intrusion from the collar of the T-nuts. It wouldn't hurt to make them a hair shorter than flush to allow you room for snugging down after epoxying.
Insert the T-nut (from the inside out) line up the swivel and insert the screws. Snug up the screws and mark them for grinding. You are going to grind the screws to fit flush when penetrating the inside of the stock though the T-nut. After grinding the screw, there should be no intrusion past flush.
Once you have dry fitted all pieces to a perfect fit, prepare a two part epoxy. I assume you’re using the original SA socom stock, so use something compatible with plastic. Apply the epoxy to the washer portion and collar of the T-nut and slip through the two holes. Align the swivel and insert the screws and snug down. Be careful not to epoxy the swivel to the bottom of the stock, you only want to epoxy the T-nuts from the inside and the hole, wipe off excess from the outside if necessary, and be very careful not to get epoxy into the threaded part of the T-bolt. I broke off a piece of Q-tip and inserted it into the threaded section until it passed through the drilled stock hole, then I removed and wiped off excess epoxy from the outside. Assemble the swivel and snug down the screws, then let it set up for a day or so and you are GTG. Don't forget to degrease the T-nut, screw and stock prior to this mission. Once the epoxy was set up, I removed the screws, applied purple lok-tite and tightened them down. Pic #3 depicts the inside section of the stock and #4 the outside with swivel attached.
