I recently purchased a Model 66-7 and went to the Catalog to date it. The Catalog says M66 production stopped in 2005 with the -6 upgrade, and resumed in 2014 with the -8... I'm confused. The serial number is DAMxxxx, which is also not listed in the Catalog.
Going back and searching for M66-7 on Google shows several people who purchased -7's between 05 and 13.
Mine is a 2.5" with the 2 piece barrel.
Anyone know the story behind the -7's?

The 66-7 and the 65-8(I hope I got that right) were the last K frame magnums produced before the introduction of the Model 619 and Model 620 in 2005.

These guns were replaced, because there is really no true weight difference between a K frame magnum and a L frame with the same profile barrel. For example, the 619 and 620 weighed in at 37.4 and 37 ounces. The new model 66-8 weighs in at 36.9 ounces. The 686 Mountain Gun weighed in at 35.5 ounces. Sadly, due to poor marketing, bad timing, and concern over the two piece barrel (and another feature I will not discuss), the 619 and 620 were stillborn. This is a shame, as these guns offer great size efficiency without the downsides of the K frame magnums (clearanced forcing cone or deleted gas ring on new models). They also allow the option of a seven round cylinder, with offset cylinder notches.

S&W brought back the K frame Magnum in 2014, I believe.