A Sportco was usually able to be tuned up to shoot military ball ammo very well. The 1:14 barrel was tight, to suite ball ammo that was often smaller than 308.
Your rifle will shoot NATO ball, 150, 155, 168 and 175 just fine. Find out what it prefers and have fun.
The two most common tune ups to the rifle was a bedding job and a third action screw into the center of the action. It is a single shot, so the bottom is solid. A third screw helps control the pounding of a 308. Not needed on the 223 version.
The receiver walls are massive - the thickest I have ever seen on any action. The bolt has three locking lugs. These turn into the lugs machined into the back end of the barrel. The bolt head is held on with a pin. Pulling the pin allows the bolt head to be changed to a 223 head, much like a Savage bolt head. The original pin was discovered to be too thin and for safety you should make sure the bolt has the heavy pin installed.
My first target rifle was a Sportco. I did well with it and when I moved up to a Grunig my wife took it over and she did well with it. I have four of them now, including a 223 and a presentation model in 308 my son won.
When the time comes to rebarrel the rifle, cut off the existing barrel stub, bore it out and machine threads in it to take the new barrel. Called an "adaptor" so you can use any barrel. The blue original barrel was good for about 2500 shots in 308.