I just bought a very nice S&W 639 yesterday and haven't yet settled on a carry load for it. I'm planning on trying out a variety of 9mm JHP's and obviously thoroughly testing whichever I settle on. That being said, I'm particularly interested in testing loadings which have a reputation for causing feeding problems in older guns. My thought is, if it is reliable with 9mm loads known to cause feed issues in older guns, then it's more likely to be reliable with other loadings that don't share this reputation (I like to have secondary and tertiary loadings of choice if the primary one becomes unavailable). So, my question is what 9mm loadings are you all aware of that are notorious for unreliable feeding in older pistols? I'm not really worried about ending up with a bunch of ammo that I can't use because if the S&W won't feed it, my CZ-75 likely will (it's been boringly reliable with nearly everything I've tried in it over the years).