I've been looking for a good "cheap" low profile mount for my ML for a while that allowed me co-witness the sights and also to remove the red dot and still retain zero after I put it back on repeatedly. There were a lot of nice quick release ones that fit the bill, but the cheapest was over $90+ dollars which I couldn't justify the price, Yes they are very nice, but repeatable zero was more important than the quick release function. How often does anyone "race" to take it off anyway?
Well, I stumbled across Aimpoint's new picatinny specific ring for the ML and it's great for the price of $22. The old stock style was split vertically through the rings and the problem was that when you tightened it, it was also tightening the scope in place, and vice versa, when you loosened it from the rail, you loosened the ML so it would lose zero. Plus you needed a allen wrench to take it on or off.
The new wide ring now retains the scope completely seperate from the rail tightening process. It also uses a square through bolt (versus the old skinny round) and has a low profile thumb screw for tightening. Four bolts retain the top half of the ring tightly against the scope to the bottom half. THe only problem (for some) will be that Aimpoint did not blacken the bolts and thumb screw. They are a "very" dark stained brass color. I kinda like it as it adds contrast without worrying about it shiny.
Hell, I don't know why anyone would want the rail grabber model now. It isn't any faster to remove or put on without tools, and the only thing the rail grabber has over it is the torque limiter. I don't manhandle my stuff, so I don't care about the torque feature.
As for quickness, it took me less than "two" seconds to remove. One second for the initial loosening of the thumbscrew and to "spin" it off, and another to flip the scope off. The thumbscrew/knob does not fall off when you spin it as it has been staked in. I can't see it being much faster with the other "quick-release mounts I have seen.
For you worried about co-witnessing the irons, my setup is an AR15 flat-top with RRA tactical handle and it will co-witness on mine. The original stock rings measure .20" off the rail, while the new rings measure .25" off the rail. My irons now site a bit lower in the tube, but they are very viewable still.
For managinging the torque on the rail, the thumb screw has a slot in in to take a screwdriver or coin if needed. I just line up the slot to the same poition each time and it has retained zero well. The only problem I could see is that if you were wearing very thick gloves the thumbscrew might be harder to grasp, but big deal. I actually prefer the lower, less snag, or jab you in the side thumbscrew over the railgrabber's big screw.
For a setup like mine and for the price of $22, it's great! For those of you who mount directly to the receiver, you will need a spacer of some kind.
If you want to see it, go to aimpoint site, products, mounts, and scroll to the bottom.