The AFPG on your barrel stands for AIR FORCE PREMIUM GRADE. These were match rifles built at Lackland AFB. You absolutely scored, even if only the barrel is AFPG. We'll need more pics or info to determine if the rifle is an Air Force match rifle.

These are the best of the best and super-duper rare. IIRC most of them were eventually made into drill rifles.

Is it 7.62 or 30-06? Is the barrel also marked NM? Any other NM stamped parts? Can you get us a good picture of the rear sight base and windage knob?

Awesome rifle!