Generally speaking, relatively minor changes in bullet weight will not have an impact on functional reliability. Note I said "generally" as there are some exceptions. I don't own a Kimber Solo, but I've been told that they will not function reliably with 115 gr. JHP 9mm ammo, but they will with 124 gr. JHP 9mm. It's my understand that Kimber's owner's manual for that gun states that only 124 gr. ammo should be used.
I've never had a malfunction of a .45ACP, 40 S&W, 38 Super, or 9mm based upon the difference in bullet weight, so long as it was the same bullet design. I have had significant malfunctions with bullets of the same weight, but different design, even different HP designs.
200 rds of ammo was my personal standard for many years. I must admit that I no longer hold to that standard, due primarily to the absurd cost of premium self-defense ammo. I cannot tell students to spend $200 or more shooting 200 rds of self-defense ammo before carrying a self-defense handgun. More importantly, if a particular type of ammo isn't going to function reliably in a given handgun, it won't take 200 rds for the problem to reveal itself. You'll know it much sooner.
Another factor is the level of risk you are willing to accept. When I was using the 200 rd. reliability standard, was I really going to reject that type of ammo if I fired 199 rds reliably, but had one failure to feed or extract? The answer for me is "no." Heck, I wouldn't even reject ammo for one failure per 100 rds. That said, my self-defense ammo in all four of the semi-auto calibers I listed has been very reliable. In fact, it has been so reliable I cannot recall the last failure, if any.
I think the real questions to be answered are 1) can I shoot certain ammo well (ex. bullet weight, +P, +P+, magnum, etc.); and 2) is the ammo accurate in my gun of choice. This can be determined in far less than 200 rds. I also think it is important to practice with the self-defense ammo you carry, but only in reasonable numbers. The match and practice ammo I reload has the same bullet weight and velocity as in my self-defense ammo (230 gr 45ACP, 124gr 9mm & 38 Super). I prefer Gold Dot hollow points for self-defense, so I buy them in 1,000 rds lots so I can load some practice ammo to factory specs. This allows me to fire 100 rds or so a month with a round that precisely matches factory ammo, but at a fraction of the cost. My goal for all practice is 100 a day for 5 days a week, but that usually works out to only 2 or 3 days a week. There's no way I would shoot that much factory self-defense ammo, or even my ammo using Gold Dot bullets. This is why I want to duplicate my self-defense ammo in terms of bullet weight and velocity. Shooting either Precision Delta FMJ bullets, or Bayou Bullets coated bullets, I can duplicate the felt recoil and muzzle flip of factory ammo. I know some guys shooting in competition load to the minimum power factor to reduce recoil. If my goal was to win a match, I might do the same. For me, IDPA matches are practice for the day we all pray never comes, so I shoot full-power loads.
I won't disclose what my new self-defense reliability standard is, because I don't want other people to stake their lives on my experience. It will say that it no longer anywhere close to 200 rounds.
Chas.
