We developed the G3/1 because a lot of potential customers refused to permanently modify their rifle or stock. They requested we come up with something they could use without making any VISIBLE changes to their stock. The G3/1 is just the ticket for doing that. We devised a "tail piece" that holds the adapter tight under the rear sight tab (trunnion) on the barrel. The only modification to the stock is a very slight removal of some wood or polymer where the locking piece contacts the stock on the INSIDE. You may need to relieve the mag well also if the magazine is binding. This adapter will fit any SKS type stock. It is a "drop-in" fit for your stock. The locking piece has an added feature that allows use of your cleaning rod to lock in the rifle just like the original rifles configuration.