I have an opportunity to pick up a gently used (under 500 rounds) S&W 640 (the old style 640 in .38 caliber only and with 1 7/8" barrel) for about the same price as a NIB 640-1 (but not the 640 Pro) chambered in .357 magnum and with a 2 1/4" barrel. The old 640 has had an action job by Denny Reichard, so it has a very nice trigger. This and a few extra add-ons account for the high price.
I am wondering if there are any advantages to the old 640s that make them preferable to the new magnum 640s, or if one should still go with the slightly larger and slightly heavier magnum 640. Even if I could, I would not shoot magnums out of a j-frame, so being chambered in .357 is not a selling point for me.
I generally carry a Glock in an IWB rig and a 642 in an ankle rig. I don't see this changing regardless of which model of 640 I might buy. If I buy either, it would be used primarily as a high round count training gun (not a range gun - I have a range-only 642 for that role). There might be times when I swap out my Glock for a 640 in an IWB rig and carry a pair of J-frames, or should age or injury render me recoil sensitive, the heavier 640 may have to replace my 642, but either version of 640 could fill this new roll, and neither model is really better suited than the other.
The old 640 has no frame lock. If I buy a new magnum 640, it won't have the frame lock.
So again, given the same price, what would you all recommend - a used 640 in .38 only with an action job or a NIB 640 magnum with a nice trigger (just not quite up to Denny's standards), slightly longer barrel, slightly heavier weight. Neither would be carried in a pocket and neither would be loaded with magnums. I don't care about how much I could sell one for vs the other - I don't intend to sell whatever I buy.