Ruger SP101. It's heavier than that 340 and that's a very, very good thing. You ain't talkin' concealed pocket carry here, just sliding it in your back pocket, the SP101 will do that. I cringe at the thought of shooting buffalo bore 180 in a Smith 340 and, in fact, Buffalo Bore recommends against it due to probablility of bullets pulling their crimp in that ridiculously light gun. It'd probably do damage to your hand at any rate. They kick pretty hard in an SP101, but with a Hogue grip, they ain't too bad. And, the stainless construction of the gun is great for outdoor carry and rust resistance.
I have a 180 grain handload that, out of my 2.3" barreled SP101, puts up 1306 fps/682 ft lbs, enough to stop anything up to black bear and it's quite accurate out of the little gun, too. A 3" gun might not fit the back pocket scenario, but has advantages for outdoor use.
In .38 special only, there's tons of choices. I'd get a stainless J frame with a hammer spur for single action shooting (in the field, SA is desireable). Something like a M88 Rossi on the low end, or a M60 Smith in either .38 special or .357 magnum on the high end. I had a M88 Rossi that was a quite accurate little gun, but replaced it with a M85UL Taurus that's also a fine shooter and lighter. It is stainless/alloy.
For outdoor uses, though, I'd get an SP101 in .357 magnum if I were you. You might desire the .357 capability someday and, it ain't THAT heavy. I'd put it in a small belt holster, though, for outdoor carry.
