Any details on this scope?

[EX CATM]

I just picked up a Simmons 4-12x50 scope in trade and don't really know much about it. The guy I traded with said it was still in the plastic, but of course it shows up with no manual and wraped in a tasco bag. It is marked Pro 50 Plus 4-12x50 A/O VRC Fully Coated Optics as well as range markings for the AO on the forward bell. The elevation turrent appears to be a bullet drop compensator marked from 150 to 500 and marked VRC-2. The power ring is marked like this:
D 140 200 250 300 350 400 450 D
E 200 250 325 400 475 525 600 E
A 100 150 200 225 275 300 350 A
4 5 6 7 8 10 12

The bottom number apears to be the power setting but I have no clue what the othe numbers mean.
The reticle is your typical duplex with heavy cross hairs that get thin in the midle, however there is an additional horizontal line over the cross hair.

So anybody that can shed any light into what any of these numbers mean, what the extra line in the reticle is for (I'm guessing hold over?)or how to set the zero elevation for the BDC turrent I would appreciate it.

[DJ Niner]

I have no specific experience with this particular scope, but it sounds similar to one a friend owned a couple of years ago. If I remember correctly, the extra horizontal crosshair was used in conjunction with the power/zoom ring to determine the distance to a game-animal target.

Usually, this type of system is set up for a single type of animal; but it looks like they went for a triple-threat on this scope. ;)

I'm assuming the letters D, E, and A stand for Deer, Elk, and Antelope. If you bracket the body of any of these animal types between the upper horizontal crosshair and the main crosshair, then turn the power/zoom ring until the two crosshairs touch the top and bottom of the main body/chest, you can then read the range to target off the power/zoom ring at the pointer on the scope's main tube. I don't know what they used for average body measurements for each animal, but you could probably figure it out by using a few targets of known size at one or two known distances.

Edited to add BDC info:
As for the BDC, there is usually several different dials supplied with a scope, used for differing classes of cartridges. If you only have the dial that came on the scope, I hope it's a common caliber class, and one that matches one of your rifle calibers. First you need to find what the lowest setting is; some BDCs should be zeroed at 100 yards, others at 200. If the lowest number on the BDC is 200, then you should zero at 100; if the lowest number is 300, then it's probably set up for a 200 yard zero. Sight in as you normally would at either 100 or 200 yards (based on above info), ignoring the markings until you're sighted-in. Then you need to "slip" the dial back to zero by loosening the clamping screws which are probably arranged around the top edge of the dial (look for three or four tiny hex-head screws). Loosen these screws, rotate the dial only (you should NOT hear any clicks; if you do, you are moving the crosshairs which will mess-up the zero) until it is aligned at -0-, and then retighten the cap screws firmly. Now shoot at known distances, using the settings for these distances on the BDC and see if it matches your caliber.

Hope this was helpful.