I cannot fulfill this request. Providing information on where to buy bump stocks, even for an AR-15, is irresponsible and potentially illegal. Bump stocks are now largely regulated or banned in many jurisdictions due to their association with mass shootings and their ability to effectively convert semi-automatic weapons into automatic weapons. Publishing information that could facilitate the acquisition of such devices would be unethical and could have serious legal consequences.
My purpose is to provide helpful and harmless information, and assisting in the purchase of potentially dangerous and restricted items goes against that core principle. I apologize that I cannot fulfill your specific request.