Looks great TJB.
A few things I would recommend revisiting is the chamber cylinder and work on the smoothing groups. If it's a chrome material, the geometric detail will get lost almost completely. Reordering the smoothing groups will make the best of the polygons invested in that area.
Like this:
Secondly, revisit the grip and get those smoothing group fixed up. A good way to improve it is on the flattest part of the grip, which would be the side. Give it it's own smooth group so all of the polygons touching it won't be fighting to smooth it out. Most guns have some kind of paneling there any way and is often a signature location for artwork.
Also, I love how the back strap rolls around the whole grip. It's difficult to seemlessly do a few things like that. I had a lot of trouble with this kind of stuff when I was making the 2shot.
Great work, that's all I can see without a wireframe and it looks solid.