The .243 AI rifle the OP bought was one I bought from a campfire member back in 2013. I went back through my records and this is what the original owner said about the rifle and the smith that did the work on it'
"Action is Sako's L579 and the barrel is a Sako sporter take-off re-chambered by Larry Cribbs of La Grande. Twist rate is 1-10, barrel length is approx. 23" muzzle to chamber, muzzle diameter is .640". Stock is a lightweight Brown Precision with a 14 1/4" length of pull and krylon earth color. Stock trigger, no sights."
Larry Cribbs competes in and builds rifles for NBRSA so he did a precise job on the barrel and the smithing. Whoever did the stock work was less talented but the rifle shot very well so I left it alone, I had never owned a Sako before so it scratched an "itch" for me. I reloaded for it and it came with 80 fireformed brass and 20 new cases and Redding 243 ai 40 degree dies. The OP doesn't reload and didn't want the dies or brass. I pretty much only shoot, .22, .223, and my Dad's rifle for hunting nowadays so I didn't use the rifle like I planned to and sold it. I would be surprised if the rifle doesn't do fine with factory ammunition before the OP eventually re-barrels it which he said was his longer range plan for it. That said, I have a .223 AI that was smithed by I,T, & D and with some of the re-manufactured ammo based on military brass the cases will show incipient case-head separation. It fire forms fine with factory new ammunition and I get good case life.
