I have a 196 mini-14 (skinny barrel). I added an Accu-Strut LT.
My groups really did shrink in roughly half. Of course I only have Iron sights (no scope mount, I don't have the Ranch Rifle), but from what I have seen, its $100 well spent. The Stainless finish matches my stainless gun almost perfectly. All of the imitators (Accu-strut is the original) use aluminum and NONE of them match anywhere near as well to the finish of the gun, yet charge more!
If you have a skinny barrel mini, it should be on the list of things to buy. If you have the newer -581 series with the tapered/thicker barrel, I don't think it will help much if at all.