I have a Redhead Pursuit 3-9X40 A0 muzzleloader scope with a drop compensater that goes from 10yrds all the way up to 300yrds and after you pass the 300yrd mark it will turn all the way to something that looks like a side ways 8.

What I need to know is when I sight it in lets say at 100yrds do I set the compensater to 100yrds? Not for sure if the scope has the same paradox as a regular muzzleloader scope??? Aslo what does the side ways 8 mean??

I know these ?'s may be silly but I have never used a scope like this on any gun. I went to Basspro website and they don't sell it anymore also done a google search no dice there either.

Sideways oo ='s infinity - so if you are shooting a range longer than is on the adjustable objective - then you should be on that setting to get the correct parollax

If you do not know the range then set the objective to what you think the range might be... If you are close and look through the scope everything should be in focus with the crosshairs.

Hope this helps - but keep asking question if it did not. I have a 4x16x50 scope on my .17HMR with the adjustable objective (AO)

Sight the rifle/scope in at the range you expect to shoot mostly. If you will have an average hunting shot between 40-60 yards, sight the rifle in at 50 yards with the compensator set at 50 yards.

Redhead Pursuit is not an expensive scope.
In lower-quality scopes, there are other sources of parallax. If the reticule is not precisely placed the correct distance from the objective, the distance of no parallax will be exaggerated.

You can check the parallax of any scope by sighting an object at normal shooting distance (not indoors), by moving your eye side to side (then up and down), as far as you can, keeping the sighted object within the field of view. The apparent movement of the reticule in relation the target is parallax.

The parallax increases with magnification.

steve, what you have is not a drop compensator. it is a parallex adjustment on your objective lens.