I apologize for the very poor picture quality, but of main interest is the alignment pins. If you'll note, the pins are steel and they go into steel bushings which are pressed into the mould blocks. No "Steel on aluminum" as in Lee's other mould blocks.
Lee block, sprueplate and sprueplate lever and cam. In order to ease the initial cutting of the 6 sprues, Lee has placed a cam on the end of the handle. The face of the cam bears on the side of the block. This arrangement greatly amplifies the force the sprueplate exerts to start the cut. A neat idea.
Over time, and especially with hard alloys, the cam WILL begin to erode or cause a depression in the aluminum (the old steel on aluminum thing again). You can stop this by drilling and taping the block for a simple steel setscrew for the cam to push against. Or drill and press in a steel pin.
End view of the mould blocks. Another poor photo, sorry. Blocks are substantial. Closest on the left block is the sprueplate holddown bolt. A headed bushing is sprung via a wave washer. The sprueplate slides under it and is held in place ( a prime lube point to be watched. It's another steel on aluminum deal.
The prime reason for going with the Lee 6 cavity mould, besides price is:
PRODUCTION!
...............Buckshot