Some years ago, I got a 3-9 Nikon OMEGA scope for a T/C Omega muzzle loader - not sure what you feel is appropriate for magnification, but I found that BDC250 reticle pretty awesome - I did not appreciate how much drop there was with 50 cal muzzle loader over distance. Not sure Nikon makes or sells rifle scopes any more, but something to look for - a bullet drop compensator feature in the reticle that matches up to trajectory of your muzzle loader. No doubt there is/was alternatives - I guess I bought into the Nikon marketing at the time. Is possible / probable that where the vertical lower post gets thicker - on Leupold Duplex, for example - might serve as an aiming point for some distance.
It has been my impression over the years that the less expensive scopes tend to "cheap out" on the quality of the guts that hold the reticle in place - the turret connections, etc. - so if you are into re-setting your scope for each shot - inexpensive scopes typically do not last very long. But if you can eventually get one sighted in, and then do not touch the turrets, some work very well - some last a very long time - but have to learn to hold off your aim for windage or elevation, which seems anathema to some shooters.
I constantly get mixed up between First Focal Plane and Second Focal Plane - one or other will vary the location of that lower point on the target as the power is changed - giving some more options for multiple aiming points without messing with turrets - although now messing with power ring, which likely is of similar quality, inside, where customer can not see that.