.308 ishapore extraction issue

Some years ago when they first came out, I got a .308 from SOG. The stock was a mess, but for $60 or so; I'd take a chance. The bore was pristine, so it had been shot a little and carried a lot. I got a new stock from Numrich and set about a rebuild of sorts. Did the furniture in auto body primer flat black, it's durable and it reflected no light and didn't look bad. Then came the extraction problem. I had fed it only handloads, mid-range .308 with 165 grain Sierra hunters, (IMR 4064) and it shot but good-especially when I scoped it with a Bushnell 9 pwr. The extraction issue was taking the rifle out of consideration for anything but a single shot hunter, nothing more stressful than that. Recently, I got a new magazine for it from Numrich and finally, on the advice of a friend; put a new $4 "extractor screw" in the rear of the receiver-absolutely the last thing you would think of as a problem-and now, she works, she works good and says she's ready for anything.