well theirs not much i cant order from springfield with the rifle, i can choose on a M25 (the Carlos Hathcock version),or a super match, the SA site does not give MOA for the M25,but does state the Super Match will do Sub MOA with match ammo, i figure the m25 does the same. I can get a Hart, Douglass or Krieger heavy stainless barrel as an option on the national, super,M21 &M25, the only thing differant i can tell from the M21 and M25 version to the National and Super match is the Stocks(wood synthetic, USMC camo ext...) and that the M25 carry no iron sights and a diffenent muzzle break, plus the M25 uses a rail mount and the M21 Has what i think they call a H-bar mount for optics, it mounts to the side. the National and Super has no optic mounts with it "option". I havent broken one down to see how smooth the action is but if i remember right their hand assembled at the custom shop so their shouldnt be much to fix. the only thing i can think to add to a SA is the McMillian M2A stock in tiger stripe DuraCoat, pick my optic mount and a US optics 10X, sorry so long, hope you get everything i said