Can't answer the question and I did look on their site as well as download directions but I can say the stock is solid and feels great. Ordered one for a Rem700 and it arrived today. I also have a LSS and a LSS-XL and I can't say for sure but the FDE panels in the summer sun may make the XRS my more favored. Time will tell. It is super nice there isn't anything else to buy like buttock or grips.
I liked the angled one more than I thought I would have but installed the vertical anyway, my normal. Watch when changing grips. The screws have washers. Took 10 minutes to find the last one on my dirty shop floor. They are rubber and very very grippy. Buttpad is very grippy also. I'll be adding a pic rail for a bypod and removing both swivel studs. Also will fingers a neoprene or foam cheekpad as its a little slick. Most are.
Stumbled on this post and wondered if the op got this stock? I was looking at it also for a CZ 457 and wanted to know how you like it? Any problems inserting the mags into the magwell? If you got it please post a couple pictures, one being the magwell area with a mag inserted.