When they say "factory bolt action 22lr's," I'll assume that they're NOT talking about Winchester 52's, Vostok Ural's, Anschutz, or EAA Ural 5.1's? If the Winchester 52 is legal, then I'd see no other choice anywhere near as good. I've owned 3 Smallbore Competition rifles, and if they're legal and you were the only one shooting one, even if you're a moderate shooter, you'd run the show at that match.
If those target rifles mentioned above are NOT legal, then the ONLY choices in my book are the CZ 452 and 455.
I've owned an EAA Ural 5.1 and two Win 52's as target rifles, plus multiples of each in Savage, Marlin, CZ, and Ruger bolt action rimfires for hunting, and I'll comment that there's a big gap in accuracy between the target class and the standard class, and a sizeable gap in "off shelf accuracy" from the CZ's to the others. I have not owned but have handled a Ruger American Rimfire, but I have heard that it's quite accurate thus far, but I haven't seen it be significantly more accurate than the Savages or Marlins, or the Ruger 77/22's (just uglier).