i have a real nice m70 243 i baught 6 months ago. i baught it used and looked up the numbers and it was made in 1965. i couldnt believe it when i read that. it looks like a brand new gun. it is bedded, blueprinted, floated and has a trigger. i have put about 500 rounds down it and one day it will keep 1/2 moa or under and the next day not so good. is it getting to be that time? if so what can i have in rebarreled to?