AOD I have a 91/30 repro that is my Cadillac, A-1 ,etc ,etc, etc (said another way its my favorite milsurp). I bought it from a guy here on the boards. Anyway normally I read posts where guys claim every freaking milsurp they buy shoots MOA bla bla bla. It's been my experience that milsurps are good for 4" groups at 100 yards if you are lucky and normally I am not. But I must say that I purchased some of the Bulgairian LB in the 300 round tin that folks say that have seen split necks and misfires from. I went to the range and shot it from my repro and WHAM it shot 1" groups, ok maybe 1 1/4" at first but it seemed the more I shot it the better it got. Some groups were actually less than 1". So I buy a can every chance I get. I also have purchased some Hungarian (800 rounds) but have not shot it. So in closing I would say buy some of everything, test it all out and go from there. If you get something your rifle does not like wait a year or two till the ammo dries up and sell it on the board here. You really cannot go wrong.
Each rifle will generally like something you feed it. The date of the rifle is irrelevant on how it will shoot. Generally the rifles will like the light ball ammo but were designed for heavy ball yellow tip if you can get it. I would buy a few packages of ammo individually an try what works best for you and then order more. Try AIM or DANS AMMO who offers a trial package in the past. Then order what shoots best for you.