Okay, I touched on this subject in another post but it became obvious that a more specific thread regarding caliber changes in the same size gun could be interesting. My situation is that, regardless of the season, I wear the same type clothes at work year round. Because of this I do not have the option of moving up to a larger gun during the winter months. I have to have something that conceals easily and comfortably. Up until now I have been carrying my Kahr PM9 and it really fits the bill. Now that cooler weather is here I start thinking about penetration since people coming in tend to be wearing coats and sweaters. Since, as I said before, I cannot move to a larger gun I have to make the choice between keeping 7 rounds of 9mm or moving up to a .40s&w round in the same gun...sacrificing the additional round I get with the 9mm version. I personally made the decision to give up the extra round and go with the round that performed better in penetration test a friend and I did with denim and other coat materials. I picked up the Kahr PM40 from Cocktailer today. Now I just need to decide whether or not to keep the PM9 or sell it since I have the PM40. What choice would you make if faced with the same options? My dress style at work.