Just got my 243 Ultra Varmint 2 weeks ago....have only shot 10 rounds from a monopod at 25 yds to get the scope relatively close,,and that was a pretty cold/windy outing......but I'm on the bull at that range........Using Hornady 58gr. V-max factory loads,,, heard good reports on that ammo.
I swabbed the bore and the chamber real good with bore polish before I shot it,,as per the many other posts I've read about these guns,,these guys that post really seem to know their stuff,,and it doesn't hurt to follow their direction,,if it sounds like it might help!!
I'll watch for other posts about the 243 and will add my own experiences when I get back out to really see what the gun will do at farther ranges,,just need the weather to get better here in Ohio.