For a M642 Airweight? They weigh nothing and are barely larger than your overstuffed wallet. One of the EDCs in my lineup has always included a S&W J-frame, which I've belly-carried (appendix-carry, nowadays) in a well-worn (and restitched a number of times in 40+ years) Safariland metal-clipped IWB. The leather is thin and flexible, with slick-side in and sueded-side out, to keep the thing secured by friction AND the very nicely polished stainless spring clip. You don't even need a belt... it grabs the waistband on those Levis quite securely. Lift the front of your T-shirt and yank that puppy out!

That reminds me... there's a few pulled stitches on it now. Need to get out the handy-dandy awl soon!