J, As Killswitch mentioned, lets turn this thread into something you can benefit from.
First off, many shooters are referring to "zeroing" your turret. This is a very important concept to grasp, as it allows you to have a constant frame of reference to orient your elevation corrections from. When you set the "0" of your turret @ 100yds, any elevation corrections dialed will always be UP from that baseline zero. IE, you will never have to dial below the "0" on your turret...
To do this, you simply need to get your rifle's POI hitting dead on @ exactly 100yds. Don't worry about what value your ele. turret is on, adjust the scope so that your POI is true @ 100yds.
Now that your rifle is zeroed @ 100yds, you need to "zero" your turret to match the rifle's POI. Do this by lining up the "0" of the turret with the zero line on the scope body. Follow along...
1. Take the proper sized Allen key and loosen the center screw on the ele. turret. Make sure to hold the turret body, so that it does not 'click' UP or DOWN.
2. Remove the screw completely.
3. Slide the turret body straight up and off the splines of the turret housing. Make sure you don't 'click' UP or DOWN
4. Orient the "0" of the turret body to the hash mark on the scope, then slide the body back down onto the splines of the turret housing.
The "0" mark on the turret body should now be perfectly in line with the hash mark indicator on the scope.
5. If so, replace the center screw and tighten with Allen key. Make sure to hold the turret body when tightening so you don't 'click'
Voila, your turret and rifle's POI are now matched and "ZEROED" @ 100yds.
You now have a constant baseline to adjust from, and return to.
You can run your ballistic app with a 100yd zero, and all of your corrections for incressed distance will be UP from that set "zero".
You can now check and confirm this "zero" @ 100yds anytime you wish, to accuracy test a new load, or whatever. The main idea is the importance of having known distance reference point to work from...
Now, if you want to set your rifle's POI to 300yds for your practice, simply adjust the turret UP to whatever MOA value your ballistic app tells you.
Confirm that by shooting @ 300yds and remember that MOA value as being your 300yd correction!
Do the same @ 600yds, and take note of that MOA correction, too.
You are done.
And you are now using a numbered turret as it was intended to be used. Those numbers are there for a reason...
Good luck & good shooting!