The tables are easy to make in Excel. I have ones that are out to much further distances with 0.1 mil increments that I use in matches that you shoot with a partner. The spotter uses them because they're impractical for the shooter to use. Too much data...
While his intent may not be to compete right away, it was clear from reading his posts that the kind of shooting he was interested in was the kind being done in PRS. And if he's having someone teach him, he would probably like to try it. That style of shooting emphasizes both speed and precision. While there are stages in a match that involve slow, deliberate shooting, they also have a lot of position shooting and shooting off of barriers, and there is almost always moving targets (which are never at the same distance or the same speed). Time is always a factor in some way. It's a style of shooting that is practical, and you also develop skills that carry over to things like hunting.
Having a reticle that you can always use has a lot of useful applications. Ranging is not the main utility of the reticle. You'll use in it situation where you don't have time to dial, in lieu of dialing. They show this in the "Art of the Precision Rifle" video, but they take it to an extreme. If you have the time to dial, you're going to dial because it's more precise.
The reticle also allows you to reduce the amount of data you need to remember or carry on your cards. This is especially true in some situations like for moving targets (useful for hunting).
Lets say you wanted to lead a moving target using a linear distance. You would need to hold a different amount for each distance and for each target speed.
And that's a table of distances evenly divisible by 100. What about distance in between? You have to figure those out on top of that.
Here's a trick with the reticle: if you use its hash marks to lead the target, the lead in mils is the virtually the same for a given speed of target over a large distance. Here is the ballistics table for a 1.5 MPH target:
Notice the lead in mils stays almost constant? Well, that means that instead of using the first table, you can use one like this:
Much easier to remember isn't it? Or easier to read off of a card on your forearm... All you have to do is estimate the speed of the target, distance is not a factor. Even if you need to adjust a little for the faster targets at further distances, its still less info to remember or look up.
This isn't something I came up with, its well known and taught at places like Rifles Only. Companies have even integrated it into their reticle:
Look at the numbers above the horizontal crosshair and look at my table. Those numbers aren't just for the quick ranging features, they're also used for leads on moving targets. You lead a 6 MPH target ~3.9 mils (depends on caliber and load). Look where the 6 is on the vertical crosshair! Look at the other numbers.
Also... notice that this is a mil based scope and they've implemented these little shortcuts in inches, miles per hour and yards. Americans think in inches, yet most of the shooters making it to the PRS finale have
switched to mils. Mils are faster and easier regardless of what system you're more comfortable with.
Know what MTC turrets are? They're turrets with a heavier click every 1 mil or 1 MOA. They let you dial without looking at the turret. That's useful to military shooters using nightvision, when they can't see the numbers on the turrets. Or, maybe they can't raise their head to look because it will give them away. It's a useful feature for competition shooters because its lets you do the majority of your dialing without looking at the turret, which is sometimes useful in PRS type matches. You only need to look at it near the end of the adjustment (after you feel the last MTC). The MOA number is much bigger. If I need to dial 6.2 mil, I only need to count 6 MTC clicks. The equivalent MOA would require counting 21 MTC clicks. Not practical to use without looking at the turret.
Before they had MTC: How many clicks in 3.9 mil: 39. How about 2.2 mil? 22 clicks. Now try that with 18.75 MOA as fast as you can. How many clicks?
FFP and mils do make a difference when speed is needed.