The 638 has a shrouded hammer that is accessible for single action. For pocket carry a lot of lint will get in the shroud (I know, I had an alloy version).

The 640 has an enclosed hammer. It can only be fired double action. There is no access to the hammer.

For personal defense I can think of no situation where single action is appropriate. Additionally the spur to lower the hammer on the 638 is very small and makes that operation extra risky.

Also look at the 640 Pro. It comes with a real rear sight, an XS front night sight and moon clips for rapid reloading. I think this is a better choice (I'm going to buy mine this afternoon).

http://www.smith-wesson.com/webapp/w...layErrorView_Y

The 642, though DA only, has a trigger that can be "staged" for more carefully aimed shooting. It took a bit of practice, but I learned to pull the trigger to the break point and hold it while settling on the target, and then squeeze off gently. It's likely not the way you would fire it in a self defense situation, but if you want to hit something small at 10-15 yards, it works quite well.

Originally Posted by Bisley

The 642, though DA only, has a trigger that can be "staged" for more carefully aimed shooting. It took a bit of practice, but I learned to pull the trigger to the break point and hold it while settling on the target, and then squeeze off gently. It's likely not the way you would fire it in a self defense situation, but if you want to hit something small at 10-15 yards, it works quite well.

I used to stage my shots--even with an exposed hammer I never used single action. But it was pointed out to me that first, staging offered the same risk as single action in terms of a "light trigger" discharge, and second (and far more important) it was so painfully slow.

With practice "sweeping" the trigger can be very nearly as accurate as staging and is vastly faster. For a self defense weapon that a snubbie is, single action and staging seem be be very much in opposition to its purpose.

the 638 is quite a bit lighter than the 642 and yes the action as described above is correct. however the lcr is even lighter than the 638 at about 13.5 ozs and would be better compared to the s&w bodyguard 38 at 14.2 ozs. my choice would be s&w bodyguard 38, ruger lcr ( tie for first ) 638 and then the 642 because of the dao

Originally Posted by Packard

For a self defense weapon that a snubbie is, single action and staging seem be be very much in opposition to its purpose.

Well, I was not advocating that for use in a gunfight, although it wouldn't hurt to know that you do have the ability to hit a small target at distances beyond 7 yards. I was only suggesting that with this particular snub-nosed revolver, one doesn't give up too much with the loss of single action capability.

Originally Posted by 1jimmy

the 638 is quite a bit lighter than the 642 and yes the action as described above is correct. however the lcr is even lighter than the 638 at about 13.5 ozs and would be better compared to the s&w bodyguard 38 at 14.2 ozs. my choice would be s&w bodyguard 38, ruger lcr ( tie for first ) 638 and then the 642 because of the dao

Actually, the 638 weighs 15.1 oz and the 642 weighs 15 oz.

compare them here

Genitron.com - The Handgun Information Resource - Home Page

i stand corrected! the 642 is only 15 ozs

Between the M&P .357 snubnose and the Ruger LCR well I would just have to buy them both to be honest. I think the Ruger felt just a tad better in my hands when just holding it.

I have a 4" Ruger SP101. It is very nice. But I believe it is a good bit heavier than the S & W. And no alloy frames.

Thanks for the advice. I have a Ruger SP101, too. It's 28 oz empty w/ a 3-inch barrel and an exposed hammer. But for concealed carry, I do think one can't go wrong with a S&W 642or the Ruger LCR -- probably in .38 +p.

I have a 340PD and a 642 both with work are accurate I group at 25 yds and hit targets at 50 yds . Both had packymer grips which make them feel better than a LCR both lite and CC is easy