Re: lowest 34mm rings
As mentioned above there are several companies out there making them, another company that makes very good rings is the one that I've been using more and more lately. American Rifle Co.
Not to be a curmudgeon here, hopefully I can explain why it is difficult to find a lower ring.
Here's the issue with searching for lower and lower rings in a big tube like the 34's, 35's, and even the IOR 40's
Ring heights are usually measured from a certain reference plane (I've usually seen it measured from the top of the rail) to the center of the tube body.
If you change the tube diameter from say 1" to 35mm, that's almost 10mm on the diameter (5mm on the radius) where material in the ring base needs to be removed to house the tube. As material is removed the ring is reduced in strength, and there is a functional minimum where a ring will not perform because the design is compromised, no matter how you slice it, you can only go so low with any tube. That "minimum" happens to be taller heights for larger diameter tube bodies.
I have a 35mm Razor HD that will be mounted on my new Underground Skunkworks receiver in American Rifle Co. rings, the clearance on the rifle *might* be cut lower, however, I opted for a 1.025" height (26mm) set of rings from ARC because of 2 reasons:
I want to use the flip up caps that came with the Vortex and I don't want to compromise the integrity of the ring.