Re: OK, let's talk about EREK knobs.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: long-shot</div><div class="ubbcode-body">The nice thing about the EREK setup is that you can move the erector assembly so a tapered base isn't required. You can basically bottom out the elevation with your zero yardage and be assured you have all the available elevation in the upward direction. I've butchered this I have no doubt, but that's the gist.
You're right that this system doesn't require a tapered base, but the 20 MOA base was a bit of a standard and sometimes more available than a flat base.</div></div>
This is obviously completely wrong but since NineHotel seems to have confused everyone, I figured I'd take a crack at it...
The location of the erector inside the tube when zero'd is purely a deterministic outcome of physics and mechanics. The erector will be where it needs to be so that the line of sight through the scope intersects the trajectory of the bullet at a certain location. No turret design is EVER going to change this fact. The turret is just a means for accurately stepping the erector screw up and down in a repeatable manner.
However on the subject of using a flat vs 20MOA base...
You've got a little round piece of glass inside there with the reticle engraved on it and it has to move up and down in order to effect how the reticle is oriented relative to your LOS. When that little piece of glass bumps into the top or bottom of the scope tube then that's as far as you can go.
The 20MOA base tilts your scope downward so that when the scope is zero'd the reticle is sitting much lower in the scope tube than it normally would with a flat base. This means that it can move upwards farther from it's starting position before it hits the top of the tube. So you get more effective elevation out of it. Again, the turret design makes no difference in this.
What NineHotel was referring to is because the scope tube is round that little piece of glass has more room to move left and right when it is centered than when it is at the extreme top or bottom of the tube. This isn't an issue at the bottom because you generally don't need that much windage at short range, but at long range you can run out of room to move the reticle left or right if it is scraping against the top of the tube when you've dial on 10 Mil. By using a 20MOA base you make that 10Mil point lower in the scope tube so that there is more width to let the reticle move left and right and so you have more available windage at those ranges. Obviously if you dialed even MORE elevation then the same problem would return, but when you've dial 16Mil instead of 10Mil.
Again where the reticle is positioned in the tube @ 10Mil above your zero is NOT effected by what kind of turret you have but rather by what kind of scope base you have (20MOA, 30MOA, flat, etc) and your height above the bore.
The EREK is nice though, no denying that.
