So I've been on the fence about getting a G27 for summer carry. Of course one of the bonuses of getting it is that you can drop different barrels in it to shoot 9mm or .357. I think started thinking of what the benefits of shooting .357 are. The .40mm would be the SD round, the 9mm would be for target practice. What role is there for the .357 to fill? Just wondering if buying the extra barrel would be worth it. please enlighten me, friends.