My good ol' reliable Finnish M28, M28/30 and M39 are all capable of ELR shooting. Though I have to wonder if their Sig-manufactured barrels had anything to do with it. Even so, a Mosin 91/30 is theoretically capable of hitting a target within 1k yards with optics anyway! ... ... I hope...
This stock set that patterned itself after the Accuracy International chassis is called the Leopard Mosin stock, made by a company called Rhineland Arms.
I am really not sure if I should bed this thing. The fit is absolutely snug, so if I do bed it, it'd be light with JB Weld. OTOH, this stock is already designed for free-floating, so there is no escaping that.