Rating for installing on nak9 - Matador Arms The Sidewinder Buffer Tube

Set screws according to instructions are to prevent adapter from turning once its set in desired position. The set screws on my adapter do not extend past the make end of the adapter, it bottoms out in a 12 oclock position and I cannot set it to the right or left 6 or 9. The male end is also too short to utilize an AR buffer tube lock nut, the remaining threads on adapter since they made it so short is less than half a thread. This was trying to install on a NAK9, however I can see this also being an issue installing on my shotgun with AR style stock. For 100+ bucks I expect a product thats without these kinds of flaws.