British 4.2-inch Heavy Mortar

[horsa]

There were two main types of sights used and after the 4.2" mortars got into general issue, it seems they changed the data plates on them to read something along the lines of 3" and 4.2" mortar. The biggest visual difference on the two patterns is how they connect onto the mortar mount. One type has a socket and the other type has a dovetail. In the shot I previously posted showing some mounts, the center one uses a socket type sight and the other two have dovetail mounts.

I can try and get photos of both patterns sometime over the weekend if you need them.