Forget getting an action only, if you do find one it will cost more than than a gun, at least that has been my findings.
Another way to go would be to just get a barrel for a T/C. I`ve got Bullberry barrels in .17 AH and .17-223 that are very accurate. With the .17 AH I push a 19 grn. Calhoon bullet at 3,600 fps., and have a point blank range of abt. 290 yrds. All of that with 10.4 grn. of H-4227.