For me in Black Powder, traditional is only way to go.
It I wanted the newer inlines like traditions, CVA and TC I'd just shoot my modern.
Checkout dixie gunworks and the possibles shop for some fair prices.
Depending on what you are going to hunt and type of projectile, for reliability do the sidelock percussion.
Look for a 30 or 32 inch barrel if you are looking 100 yds plus.
28 to 30 for closer ranges.
The longer barrel will help stabilize the projectile and give a tad more oomph in feet per second.
Unless you are shooting squirrels or varmits get a 50 or 54 cal.
Both 50 and 54 are good for antelope, deer and elk if you do your job righ5.
You can save a few bucks and get them in kit form if you are good with your hands.
Mine is 30 year old CVA plainsman kit (no longer made by CVA apparently). 32 in barrel 1 in 48 twist rifling. Shoots pointed bullets and round ball equally well.