Hmm, thanks for that. I didn't know that was an option. The manual that came with mine was in Russian. Now I'll have to see if I can find the rest of the stuff that came with it and locate that tool. If I can't, is there a place where I can buy a replacement, or a suitable substitute?
You could probably take a file to the middle of a wide common screwdriver blade, or maybe take an old fork and cut off the two outermost prongs to leave the two inner prongs, or something. What you need is something to fit the two indentations in the ringlike screw (NOT the center screw, but the annular screw that surrounds it)---what is called the "spanner screw" in the pic below---while not touching either the center screw or the adjustment knob itself.
As I recall, you back that out a turn or two (WITHOUT touching the center screw) and this allows the knob to pop up a millimeter or two; you then zero by turning the center screw, and once it's zeroed or close to it, you orient the knob until zero is next to the witness mark, pop it back down, and re-tighten the spanner screw. Definitely get some translated instructions though!
If I have time, I'll dig out my tool and scan it
so that you can have something of a pattern to make a substitute if need be. It came in one of the pockets of the carrying case, with mine.
Ya know, I never understood this whole fascination of your optic MUST co-witness or its useless. When I shoot with optics, I aim through the optic, not through my irons and the optic; doing the latter seems like it defeats the entire purpose of the optics,. You might as well save yourself some money, and just stick with iron sights. So what that a Kobra doesn't co-witness? If I want to shoot irons, I shoot irons, if I want to use optics, I use optics. If my side-mounted optic on an AK craps out for some unknown reason, I use the throw lever to discard it in under 2 seconds flat, and use my irons.
One really nice thing about a cowitnessed optic is that it's trivially easy to verify zero in the field after the optic has taken a hard knock or the rifle hasn't been shot in a while; just turn the optic on low, rest the rifle on something, take a fine sight picture through the irons, and make sure the dot sits exactly on the tip of the front sight post.
I agree that a higher-mounted optic is very usable---I run a Kobra on my SAR-1, and shot USPSA with it for a while (the Kobra rocked) until switching to an AR---but if you have the option, a cowitness is nice.
My favorite thing about the Kobra is the selectable reticles. When shooting USPSA, I'd use the T-bar reticle since so much of our shooting was in the 5 to 25 yard range. In close, if you put the bottom part of the T on the target, you'll hit it; that helps immensely with the offset due to the tall height over bore. For longer range stages, I'd switch to the dot-chevron and use the chevron in close and the dot further out.
