dead deer
One gun scribe has posed the question. "At what point in the clean kill did the bullet fail" or words to that effect. And indeed, a dead deer is a dead deer.
In checking the velocities of .50-245gr/100 power belt loads it seems they will be somewhere in the neighborhood of 1750 fps. I see that as a about the equal of a magnum bigbore handgun.....exceeding the .44 mag from a handgun, but not nearly in the same class as the .454 or the .480. If one is shooting sub caliber (.44/.45) saboted bullets, they are actually duplicating .44 mag ballistics. What a 245gr at 1750 fps mirrors is a .44 mag carbine.
I've had a good bit of exposure to a .44 carbine myself, having done a good bit of whitetail hunting with one , and observing my my Dad's results with one in the '70-80's. Without side tracking the thread, the .44 mag takes deer cleanly, but it is not a Zeus like thunderbolt, dropping whitetails in their tracks. In fact, my experience is that DRT kill may be the exception to the rule, especially if one shoots their deer "tight behind the shoulder", regardless of cartridge. Exit wounds when shooting JSP or JHP bullets in the .44 carbine were a roll of the dice, depending on angle and distance (arrival velocity). Bullets lighter than 240gr did not exit in my experience. Accepting that observation may put the OP's hunts in perspective.
Personally, I am very old school when hunting with muzzleloading rifles. Iron sighted traditional sidehammer rifles of Hawken pattern , with real
BP and heavy, full caliber projectiles. My shots are close, under 50yds, usually from treestands. The old 370gr Maxi does just fine with 80 gr of FFFg from Renegade/Hawken rifles, usually passing completely thru a whitetail regardless of angle. I'll add those 370gr Maxi's are increasingly harder to find commercially, and too dang expensive when you do!
While two holes (in/out) in an animal does not insure a better blood trail, theoretically, it should. But hide slip and the shoulder blade sliding across a wound in the chest cavity, as well as the height of the wounds in relation to the chest cavity (lower exits typically SHOULD yield more blood) make blood trails a roll of the dice issue as well. Hope for it, but don't count on it.
All of that to say that when hunting with a muzzleloader, regardless of style or load, one is still afield with a firearm of adequate but relatively modest performance when compared to a centerfire rifle in the '06 class. Pick your shots and angles, and use good sense in recovery and tracking if necessary.