this (reports on SASS from swat) is similar to the groups i'm getting with my tac20 with 10xSS.
i'm not really all that great of a shooter, just getting into rifles, but i was on a bipod with a sandbag under the stock, so i was pretty steady. i'm also using the standard trigger, which breaks cleanly, but is like 6 pounds.
surely a better trigger and a bit more magnification would help.
lower weight bullets, and especially federal seem to be best and most consistant.
in reference to the winchester moly/lubrilux/whatever the crap... i don't know what it is, nor do i even care. i tried some of the xp3 supreme elite $35 a box stuff for hunting, and omfg. that was the most inaccurate ammo i've tried. out of 8-10 different brands i've tried so far i've maintained 100 yard 5 shot groups ranging from 3/4-3". then, i don't know if it's the coating or what, but i got about 8" between 2 shots, and the 3rd was off paper (8 1/2x11") with the winchester.
they shoot fine out of my dad's bolt gun, so i hate to just blame coatings like that. i don't think the tips are an issue, because the fed ballistic tips do great. it could just be a bad harmonic. who knows. i guess i could try a different coated bullet to try to figure out if that's the problem. i'm leary of moly coating anyway though. i read some contraversial stuff about it somewhere. i think i'll just swear off of the stuff.