A pox on all those at Savage who created and introduced this abomination of a rifle.
The Savage is made expressly for smokeless powder use too, but only a few very specific powders.
It has clouded the issue and probably been responsible for a slew of blown or damaged muzzleloaders NOT designed for smokeless powder.
Standard black powder guns have ignition systems, breeches, breechplugs, etc. that are not meant to contain the higher pressures of smokeless powder.
One of the weakest links in this chain is the ignition system. High pressure gases of a black powder overload or smokeless powder load (even a week one) will spurt back out the tiny hole of the nipple, blowing gases into the shooter's face.
Often, the thickness of the steel walls on the breech simply aren't thick enough to contain the higher pressure.
Higher pressures from smokeless powder can strain the threads on the breechplug, perhaps even shear them and cause it to fly backwards like a projectile -- into the shooter's chest or shoulder.
Upon ignition, the burning characteristics of black powder (and black powder substitutes) are significantly different from smokeless powder. Black powder tends to give a "slow push" when seen on a pressure curve. Pressure builds relatively gradually. Smokeless powder gives a much sharper jump upon first ignition.
Never, EVER use smokeless powder in a muzzleloader not designed for it -- which pretty much means the Savage is the only exception. May its creators all get a deep cancer.
Yeah, your old smokepole may propel a ball with smokeless powder and exhbit no damage for the first or even the 12th shot, but you can bet that the steel is being seriously strained with each shot. Eventually, it may let go -- into your face.
Smokeless powder generates much higher pressures. Plain and simple.
Don't put it in any gun originally designed for black powder, no matter what old book or some know-nothing tells you.