On a more serious, google this and snipers hide and it will kick up threads but my understanding is u just mill off the anti rotation post and it goes on.
Get in touch with Kyle at XLR and he can walk you through what's required to run the PRS on his chassis system.
Just be advised that it requires milling/modding the PRS body which will then ONLY be usable on the XLR (it won't work on an AR after that). You can also use the folding adapter kit that Kyle sells in which case, I don't think that any modification is required to the stock to get it to work (and it'll make your rifle a fair bit shorter for ease of transport when folded, etc.). I'd go that route before I went hacking up a $200+ stock body.