Stealth 10b butt stock/adaptor

New member with dumb question that I didn't find the answer for when doing a search. I want to remove the GLR-16 stock. Figured out how to do that but I tried putting on a Magpul PRS stock using the buffer tube I removed with it from an AR-15. The tube/PRS combination is about an inch from mating up to the Stealth chassis. I am assuming I need some type of adaptor. I was considering ordering a new Luther butt stock but they have several options. Trying to figure out if I will always need an adaptor, and if so, which one? Or are there buttstocks that would mate up without an adapter?:confused: