I also have the 638. I have handled 642's. I wanted the option of being able to cock the gun while still having a no snag hammer when I got mine.
After shooting it for 2 years I almost never cock the 638 any more. It shoots great double action.

The 642 has the advantage of no opening around the hammer to pick up lint, etc.

If I were buying over again today I am not sure which one I would get. I loan my 638 out during a CCW class now and again. Lady shooters like being able to cock it. With that consideration in mind, I would probably stick with the 638.

They are so close, I am not sure one has enough real world advantage over the other to say this is the best one. I prefer either to a 637 however. I pocket carry the J frame quite a bit. With a 637 I would have to bob the hammer if I carried one.

I have a Lobo Model 1 Pancake holster with inner Hammer Shield, and Detail Boned for mine. I belt carry it quite a bit also. I love the gun/holster combination. I shoot the 638 in BUG Division at the Club. This holster really makes for a smooth draw.

Bob

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