by rc42 » 08 Oct 2020, 12:05 pm
How you intend to use it is everything, but as a general guidelines for scopes:
First Focal Plane (FFP) - Reticule size changes with zoom level, great when changing zoom at a any distance as the holdover remains the same on the reticule markings, well suited to hunting but not good for target work as the cross hair can obscure the target at high zoom.
Second Focal Plane (SFP) - Most common type, if it doesn't say FFP then it's this. Reticule always looks the same at any zoom level, good for target work at high zoom, harder to calculate holdover if you change zoom and shooting distance.
Zoom/Magnification levels - low zoom good for close range work and tracking faster moving targets when hunting, high zoom best for fixed target shooting at long distance. A fixed zoom scope will usually have better image quality as there are fewer lenses but these are increasingly rare and generally just for fixed distance target work.
Parallax adjustment - Works like a focus but when set correctly moving your eye does not change where the crosshairs are located on the target. Cheaper scopes have fixed parallax at around 100m and the view can get blurred below about 20m. Cheek weld and head position is more important if you don't have parallax adjustment.
Lens size and tube size - Larger front objective and larger diameter tube let more light in so are better for dawn/dusk shooting.
Reticule - MIL or MOA? for almost everyone it doesn't matter, Google if you want the details. Illumination is nice for low light shooting and etched reticules are sharper with more detail than wire crosshairs. Lots of markings are good for holdover estimation but you can ignore them most of the time.
Cheapness/Value - Some cheap scopes are prone to self adjustment under recoil so the zero point keeps changing also the tracking can be poor on them so up/down and left/right adjustments don't move in straight lines, some also don't return to the same point for example if you move 20 clicks one way then 20 clicks back. Such scopes are junk but they look the same on the outside, beware of bargains although some can be great value.