I don’t know about the Savage, but in general, there are three reasons for a heavy barrel.
Barrels move when you shoot them. It’s called “barrel whip”. The thinner the barrel, the more whip. The heavier (and therefore stiffer) the barrel, the less whip. Less whip means more accuracy.
This one applies more to pistols than to rifles, but it still applies. A heavy barrel hangs better. The gun’s balance. If most of the weight is in the stock, it is harder to hold on target. With more weight in the barrel, with the balance of the gun centered or slightly muzzle heavy, it is easier to hold on target.
When the bullet goes down the barrel it makes heat. The more and faster you shoot, the hotter the barrel gets. When metal gets hot it moves. A thinner barrel will heat up faster, and just like with whip, move easier and farther. A thick (heavy) barrel will take longer to heat, and will move less.
For long range, I’d say the solids would be better, simply because they are heavier, so hold their velocity longer. If you really want accuracy, you might want to look into the Paco Kelly Accurizer. http://www.gunblast.com/Paco2.htm
Jacketed bullets aren’t. They have a copper wash on them. Much (much much much much) thinner than a bullet jacket. Non-jacketed bullets have a waxy lube on the bullet nose. Both the wash and the wax are to lube the bullet on its trip down the barrel, so your bore doesn’t’ fill with lead. The main advantage of the jacketed bullets is they don’t melt. If you do as I did as a kid – dump a box loose in my pocket – then your body heat will melt the lube. As you chamber the round the melted lube will smear on the case and the chamber, and may cause sticking when you attempt to eject. If you carry them loose in your pocket your body heat will melt the lube and they will pick up trash from your pocket (pocket lint, dirt) and then you put this in your barrel. If you don’t carry them like this – if you keep them in some type of ammo container (whether the original box, or something like an MTM ammo wallet) then you don’t have the melting/trash-collecting problem. Then the question of which is better is answered best by, “Which does your gun like better?”
Last question – don’t know. My one silenced gun is a 22 pistol, I don’t use it for long range, and the silencer won’t come off anyway.