FFP really makes sense if your task demands that you use ALL the mag range AND must range targets at varying mag levels.
When I am long range shooting, the mag rarely if ever changes. If I did want to use my reticle to range, I would just need to know what the subtension was at the most used mag level and 1 lower mag. AND that subtension, I would check against a tape measure at known distance. Don't trust what the manual says.... confirm
In general, our eyes don't work so good for reticle subtension thus ranging at long distances. The angular differences are very small so you can be way off in your math for a small errors in measurement. Most suggest that reticle subtension starts to get iffy beyond 600yds... I think you can go much further but you need the reticle and practise to get it right. I have botched up enough to know, it is not something you just go do.
Reticle styles and thickness play a massive role in this error. Here I much prefer the picket fence reticle like the Sightron LRMOA. Because you are dealing with a thin line, you can bracket an object so much better then using a couple of big fat dots.
If all you want is minute of APC, no problem. Something the size of a milk jug gets a whole lot more difficult. Pop can, forget it.
For many cartridges, the drop beyond 600yds becomes enough that if you are off by 25 to 50yds, you are going to miss by a few moa's. That can lead to a wounded animal or missed target.
Yes, practise, practise, practise.... helps but give me a quality rangefinder anyday.
The Sales of FFP scopes have been solid and the Sightron offers superb value. For those that subscribe to this process, an awesome choice. But for those with SFP scopes, they can do the same thing if they know how their gear works.
In fact, the process of reticle subtension changing with mag CAN help you range without the math. Very old tech used since post WWII. Know what the subtension of a certain size relates to the mag on the scope. Dial the mag until the object is bracketed, read the mag which relates to distance, engage.
If you look at scopes from the 70's and 80's, a very common feature. Obviously, it was a great idea that fell flat on its face. Likely because optical subtension is by itself, an iffy process.
Eeeny, meeny....
Jerry
