I'm going from memory here but if it serves me correctly, they made the 66 with the telescoping bolt and the 66S was a single shot.... I might be wrong on that though.

If your referring to the telescoping bolt model, I seem to remember it was originally designed as a sniper rifle for special services and the only reason they stopped making it was that they couldn't make money on the production.

Of the few I've seen, they're helluva good rifle and extremely reliable and accurate..... probably expensive even now though.