Some of you Smith experts clear something up for me.
I've had a Smith Mod 13-3 and Mod 60-3 for years. Both have 3" barrels. Naturally, I thought the -3 meant 3" barrel. However, now I've seen a Mod. 29-3 with an 8 3/8" barrel and another Smith with -1 and a 4" barrel. If it's not the barrel length, what is it?

The -# refers to S&W's modification to the base model. Thus, -3 is the third modification. When S&W incorporates a manufacturing change, they add or make a modification number change. For a more detailed explanation, see: www.handloads.com/misc/Smith.Model.Changes.asp

As Marshall mentions the "dash" number is properly referred to as a "change" number, thus third change, fourth change, etc. As odd as it may seem, the change number for a Model 29 third change means something entirely different than for a Model 629 third change, even though the guns are the same except for type of steel.

To determine what these represent for specific models, get a copy of "Standard Catalogue of Smith & Wesson", they are fully described under the specific models. Just plain a good book to have if you are interested in S&W guns also.