Mike, you do know that rule 1 with an old muzzle loader is to make damn sure it isn,t loaded. 200 year old dry powder will burn! Muddy
Sure - but there's a difference between "burn" and perform somewhere near original spec and be reliable on big game.
Well, will probably put it up for sale sometime anyway. Unless something changes, really don't have a need for a .350 RemMag, much less 250 gr loads. Held onto it this long (Rem 700 Classic bought in 1985) because its just about the most consistently accurate rifles I've ever used.
Heat and moisture will degrade stored ammo. Moisture issues, at some point you'll detect visible clues on the bullet and case. Heat issues, may chemically break down the load, having no visible clues. Storage in a vehicle during the summer can easily reach temps high enough and long enough to degrade ammo.
Absent excessive heat and moisture, I'd expect modern loads to easily store a decade or so in great shape. In ideal conditions, decades. But I'd also expect that modern loads, today, are markedly improved over loadings from a half century ago, from the get go. So in that context, your ammo from a half century ago would likely not be as tolerant to the extremes as a current equivalent.
