I only ever carry it in an IWB holster always positioned how I've trained with it, right now that is a carbon fiber Clinger Atom IWB. Pocket carry is ill advised w/ any gun. We had an officer shoot his thigh on our indoor range drawing G21F (.45) from a popular brand OWB belt holster w/ forefinger retention release. We all had to buy new OWB plain clothes holsters as they standardized the duty carry for CID after that, now has to be a certain model SafariLand OWB retention job w/ thumb release. Either belt or paddle back in that particular model is permitted.
My point being if some OWB full size carry holsters can suffer from accidental discharge (albeit retention release type), reaching into one's pocket to fumble for an unsecured weapon during a defensive use scenario unfolding in real life (dare I use the term pucker factor again) well then... no. Pocket carry is ill advised for an "oh chit!" defensive gun. Not just accidental fingering the trigger but fact that the gun is never going to be in the same configuration each time it's carried (flopping around in pocket) and so there's no consistency for drawing the gun during range practice. And I know everyone who carries puts in range time with the gun in their preferred carry position, yes?
As far as muzzle snap and the Walther .40, I've qualified with it on our range. Not approved for duty backup, that's restricted to a few specific guns by Glock either .45 or 9mm (G43 is one). We can carry what we want off duty but need to qualify with it. Issued duty piece is the Glock 21F. CID can duty carry the smaller Glock 30 (personal purchase) or their issued 21F.