It's not necessarily bad per say, but maybe not the best. There are a couple of threads on this already, but the 180 gr. bullet is sort of heavy-for-cailber in the .40. It takes up a lot of room in the casing so they can't load the powder too hot because you get a very high pressure resulting in Kabooms. Because of this, to err on the side of caution, the factory will typically load the 180gr. cartridges a little lighter in case of an accidental overload. This is not an issue in the 165 gr. It will be closer to the recoil of your self-defense ammo unless your SD ammo is 180 gr. as well (which isn't a good choice for SD ammo). If that didn't explain it fully enough someone will be along to add to or correct me lol.