I ordered a Boyd's thumbhole for my heavy stainless b-mag. (The sub question is: I gather the "bull barrel stock" is the correct one, though I always take "bull" to refer to a shorter barrel) I'm debating mounting a rail on the front grip and putting a bipod on that versus using the strap pivot. Anyone have any opinions on that? Despite having a flexy stock, I have been getting some really tight groupings at 100 yards, but that flex is total BS.