Thanks to John Tarabocchia for informing me about these!

This horn is the immediate forerunner of the famous Super Dynaction. It's also not that much different from the "Series VIII" horns: the obvious difference is just the change from the "resonator" bell-to-body brace to a flat, sheet-metal look.

I owned a Dynaction alto (yes, I had initally thought it was an SDA, but it didn't have the "Super Dynaction" engraving) and it was the all-around best horn I ever owned.  The intonation was great, the action superb (slightly more cumbersome, but a lighter feel than the Mark VI) and sound was dark and lush.  I have had two other professionals play this horn (which I summarily traded for a Yamaha 52 bari), whose main horns were Mark VI's, say that my Buffet was "comprable." When I finally got my hands on several Mark VI's, I decided that they were right. This is kinda kewl because this model Buffet is supposed to compete with the Selmer Super Balanced Action horns.

I had the opportunity a few years back to compare my horn (which was mostly mint: some relacquer and repair on the neck) with another Dynaction in a lot worse shape and I can conclude that the original setup of these horns include THICK flat metal, screw-in resonators. That not only gives these horns the traditional dark Buffet sound, but also provides a bit of projection.

As mentioned previously, it seems Buffet "restarted" their serial number charts with these horns.

Finally, it appears that the first "two-tone" Buffet horns were available: yellow lacquer body with nickle-plated keys.