In able for my 91/30 to hit to POI in relation to POA, I added a piece of small, white plastic tubing to the front sight post and trimmed to hit where desired @ 50 yards. About 100 yards is as far as I would consider taking a shot. I don't use a scope. Of the 30 head I have taken just 2 were at this range. Most were in the 20-50 yard range, a few shorter, and a few a tad further. I hunt from a ground blind and strive to get them in close and double lung them trying at all costs to avoid the shoulders in or out. Unlike what seems to be the trend for many, I do not take long or running shots, nor do I try to hunt deer like quail. Sadly, too often I see the results from those that do .
As far as finding suitable big game bullets for the rifles you mentioned , one can readily find them commercially loaded for them all. Privi partizan, S&B, Wolf Gold, Win. etc. I have taken deer with both the S&B and Privi in 7.62x54r. All 1 shot affairs. Best of luck.