Last post was nearly four years ago, but I'm resurrecting this thread anyway because I just received my new CDM Gear MTR clamp!
FROM CDM GEAR:
"The
MTR with included 3 slot rail is the latest offering in the MT series of clamps for lights with built in attachment points. This 1.7oz clamp fits in a 1/2" of space so it is perfect for the Mossberg 590A1 and just about any other shotgun with a 25mm magazine tube and room to mount it. This mount can be positioned 2 ways, left, or right, and provides a solid "lock up" around the mag tube. Each position allows for a sling to be used with the included sling mount/hand stop at the bottom. Additionally there is provision for a QD push button sling swivel built right in. Manufacturered from aircraft grade aluminum and hard coat anodized it is a superior mounting solution for those with limited space or under the gun sling mounting requirements. One tool for one bolt is all that is needed to attach and remove the clamp or light in seconds. Fits Mossberg 590A1 Heavy Millspec Barrel and Ithaca Shotgun Magazine Tubes. Not meant for magazine extensions without a clamp."
This is quite a bit different than the MTC I have on my 500 as its a narrower profile and includes a QD socket and option to mount the 3 slot rail on the same side as well as the rail mount on the opposite side. It is also ambidextrous. The bottom of it is slotted to be used as an SAP was designed as a handstop for SBSs.
It fits the heavier magazine tubes of the 590/590A1 and 835, and also Ithaca. For smaller diameter barrels like the 500, a clear spacer made of decal like material is included.
Also included is the 3 slot rail with the mounting screw and allen wrench, though the allen wrench for the mount itself is not.
I mounted mated mine to the 835 without using the spacer and will get some good pics for your viewing pleasure!