There are a lot of assumptions being made about the OP's shooting abilities. I don't believe he stated that he's only going to shoot 50 rounds per year total, just 50 rounds from this specific gun. I know plenty of competitive shooters who'll shoot 2000+ rounds per year in their comp guns and only 40-50 in their hunting guns. They never have an issue hitting kill zone sized targets well beyond the 1000 yard mark. Now consider all the rifles chambered for the Allen Mag or other CT variants. Those guns are not intended to be shot 300 rounds per year otherwise you'd end up replacing the barrel every 2 years. With high performance chamberings you get a load dialed in, and practice a couple times each year with it. As long as you have good ballistics data, any competent shooter can grab any gun and make hits a long range. As long as the shooter has good fundamentals it's just not that hard.
For the OP, just get the 28 Nosler and run with it. The only factory loaded ammo that's going to out run it will be the 7mm RUM and that's not a good fit in a Savage action. Factory ammo doesn't limit the performance of any SAMMI spec chambering, it's loaded to meet the design specs laid out by the cartridge designer. Hand loaders are just pushing the limits of the design beyond the original specs.