Two things to look for when purchasing a pocket holster for a hammer equipped snubby:
#1 Make sure the hammer sits well into the holster so as you rock the gun back during the draw the holster catches pocket material before the hammer does.
#2 The holster can't have a sewn lip on the inside edge of the opening or it will come out with the gun.
For example, the Desantis Nemesis has a lip on the inside and grabs the hammer during the draw - not a good thing.
I would suggest ordering a Mika round-cut and purchasing an inexpensive (under $10 at Cabela's) Uncle Mike's #3 for carry while you wait for the Mika. The Mika is not a do-all holster, but it is inexpensive and does work in most pockets. It will give you a good baseline to gauge your likes and dislikes in a holster.
I presently pocket carry both a 642 (shrouded hammer) and Vintage Charter Arms Undercover w/ hammer. I have also carried a model 36 in the past. Both the Mika and UM holsters work well for for me with hammer-equipped snubbies.
Clockwise from Top. Mika, Thin IWB off ebay, DM Bullard, Diane's Speedstrip Case, Desantis Nemesis, RKBA Custom Square-Cut for my coat pocket.
You may want to check out rkba.com. He makes some nice leather designs and is a member of this forum.
rd