I bought a M640 a few years back that was part of a special run for AccuSport and it is my favorite J frame. It was ANIB with only 5 rounds shot by the first owner. It is scary accurate when shooting 145gr Winchester Silvertip .357 Magnum ammo! The grips came stock on the revolver and are most likely from Badger Custom. I liked the grips so much I bought a set of Badger Custom boot grips for my current carry, a M442.The stock grips are full length rubber and these replacements are made by Altamont. They give me a good grasp for magnum rounds, don't grab clothing like rubber, and generally look much better. One issue is the grip relief on the left side. I'm going to trim it down to reduce the interference with reloads... Not a big issues, but it could be better.
Some features of the 640 Pro are: 357 Magnum capable, fluted 2 1/8" barrel, tritium three dot sights, and the rear of the cylinder machined down to accept 5-shot moon clips. It also will run single, loose rounds without the moon clips.
Weight-wise, it definitely isn't an aluminum framed Airweight. The all stainless construction adds mass which is welcomed if shooting 357 rounds. I carry it in a belt holster and leave the pocket carry to my 642-1 Airweight.
I received this gun as a replacement trade I worked for a broken 642 I sent back to S&W. They don't make many, so I had a few months of waiting. I think it was worth it.
Edmo
I believe a mis-aligned barrel, but not positive. He posted about it on a S&W forum.What issue did it have to go back to the "mother shop" for?
It was shipped from S&W direct to my LGS so he could do the ATF transfer. When the LGS guy handed the revolver to read the S/N, the rear sight fell OFF!!What issue did it have to go back to the "mother shop" for?
The barrel was "clocked" and not straight in the frame.
That is really, really common, at least among the S&W revolvers that I've handled in the past two years. The other issues, not so much.