Don't know your definition of "limited amount". I practice with standard velocity 158 or 148 gr. lead. Shoot/shot 3 cylinders of the Speer 135 gr. +P to verify POI/accuracy (shot to POA @ 5 yds.) and happily carry said load in my 642.
Hello. I have fired several hundred +P factory loads through a non+P-rated S&W Model 042 as well as other aluminum-frame S&W snubs over the years; most were Model 37's which had had their hammer spurs removed.
I believe that in most instances, a person can shoot +P in the non+P-rated snubs w/o damage. The guns won't explode or cylinder chambers blow out as can happen with dangerously overloaded handloads. The manner in which the +P loads may damage some individual revolvers is by stretching the frame. Not readily apparent just by looking at the gun, the frame is stretched enough that firing pin strikes fail to fire the cartridge.
While some individual revolvers leave the factory when they shouldn't or have weaker frames than others for whatever reason, I've seen very, very few aluminum frame J-frames damaged from shooting factory +P ammunition. I did help destroy one by continually trying to have the Airweight (Model 37) digest a few hundred "quasi-357 magnum" handloads in the '70's. It held together fine, but the frame stretched and the gun was not reliable. Sent back to S&W, it was stretched too much to be repaired.
In my opinion, you can and should shoot your preferred carry ammo in your carry snub. A few rounds now and again of +P shouldn't be a problem in a non+P-rated S&W in my experience.
For me, practice is normally done with cheap standard pressure factory loads or standard pressure handloads with a few rounds of +P thrown somewhere during the session.
This is one of the late run Model 37-2 S&W Airweights. It has no +P designation on it as does my Model 642, but it will be fed +P ammunition for carry.
I purchased this non+P-rated Model 642 used. It has digested roughly 250 factory +P loads, Remington 158-gr. LSWCHP +P, Corbon 110-gr. DPX +P, and Speer 135-gr. GD +P. It runs fine.
This Model 042 has been carried lots, shot lots and with more than a few +P loads over a period of years. It is own its original parts other than grips and continues to shoot well. I check primer strikes on fired primers with all of my handguns when at the range, but especially the aluminum snubs. So far, no problems whatsoever.
What I'm trying to say is that I believe you can shoot enough +P factory rounds in your Airweight to learn POA vs. POI and how the felt recoil is. Unless we're speaking of real dedication over a period of years, I truly do not believe that you will want to fire enough +P loads to harm the revolver.
Not that Mr. Camp needs anyone to agree with him, but I do totally.
My agency was issuing steel framed J frames at one point as backups for our issued pistols. Some of these Smiths had some serious age to them, including a couple with only a 3 digit serial number - meaning they were built before I was, and I am in my 50s now. I know we may be talking apples and oranges to a degree, but the Smiths were old enough, and none were +P rated weapons.
We cautioned our firearms unit to remember the J frames were old. They selected the Federal 129 +P JHP as the only authorized round for both practice, qual, and carry. Over about the last 10 years or so I have watched countless +Ps go down range in these guns. Beyond age and broken parts, there have never been any problems I felt were related to the ammunition.
I suspect your hand would get tired of shooting the +P loads each range session long before you could damage the weapon. Just my opinion, but it is based on watching thousands of +P go down range out of non +P rated model 36s, and many with some serious age and usage behind them prior to.
You should shoot enough of you chosen carry round to be confident of where it shoots, and of you ability to control it. I certainly would not put a steady diet through it, like we have done. But I would readily shoot 3 or 4 cylinders each range session and never worry about it. Years from now, watch for any possible stretching, which may or may not occur.