^ See those round vent holes with screening behind them? They are located just behind the capsule. The capsule is in the section with those holes.
In beatkilla's photos the capsule section is attached to the interference tube, and that combined assembly of interference tube and capsule is unscrewed from the mic-body. Often the interference tube and capsule are a single part. But maybe on your microphone there are two (or perhaps even 3) threaded junctions rather than just the typical one? One at the back of the interference tube in front of the capsule and another between the capsule and body?
I've only used the 853 cardioids, and do not have hands on experience with the microline mini shotguns, so I'm unsure of the assembly of the AT mini shotguns.
In the original photos I can see two additional feature lines around the body, one in front and one behind the vent holes. See if the section with the vent-holes can be unscrewed from the body. If so you should be able to switch to using different capsules with the same diameter.
If so, you'd change capsules by unscrewing the parts there (at the point farthest back on the mic-body), rather than unscrewing the interference tube from the capsule as shown in the photos of the original post. That will keep the capsule and its interference tube together as a unit.
Might search for the various AT miniature mics at the AT website. I bet housing diameter is listed in the specs, which should get you closer to a positive ID.