This does not fit pws(primary weapons systems) lowers - Stern Defense MAG-AD9 AR-15 Glock 9mm/.40 Magazine Conversion Adapter

I bought this to go into a future AR9 build planned to be built off a pws lower... but this is to large and does not fit my pws mag well...upon trying to see if I could wriggle it in because its pretty close to fitting it completely destroyed my well coating and severely damaged the finish on the stern defense product...as well as taking a punch and hammer to carefully tap it back out SLOWLY as it was wedged completely... it seems to be a decent product just be weary it mat not fit your receiver...I tried it in my spikes tactical it slid right in???...but that is a drilled for cali mag lock receiver which is not needed with this product as it uses a separate glock mag release..so it cannot be mag locked and can only be featureless.... So now i have to buy another receiver to build my AR9??