That was some funny stuff Guillermo ...
High strength styrofoam, indeed.
While I generally don't make specific recommendations to folks (LE and non-LE, alike) when it comes to makes, models and calibers ... preferring them to try guns & ammo combinations out for themselves in order to decide ... I have hinted that shooting .357 Magnum out of the Airlites and the M&P 340/360's (between the Airlites & the Airweights in actual weight) is probably something that exceeds the skillset of many users. Why waste the money on a Magnum J that's only going to see standard and +P loads all the time?
If they had made a M&P 340 at the time that was only chambered in .38 +P, I'd have bought it instead of the Magnum-rated one. (I realize since the introduction of the M&P 340 that the company has worked with LAPD to introduce such a model variation, though.) I bought both of my M&P 340's for the Scandium frames, the blackened (PVD) stainless cylinders, and especially for the XS front night sight. I bought the second one to have the variation without a lock (so I have one of each). I look at them as sort of "improved" 442/642's.
I've done a lot of shooting with an early stainless 640 that had the frame marked for +P+ (which was a limited model, as I recall, since the Magnum rated 640 was in the works). I used it to burn up some cases of some older Winchester .38 Spl 110gr +P+ that had been pulled out of agency inventory when revolvers were dropped for pistols. It helped blow the dust off my revolver skills (which had become idle for a few years after we'd gone from revolvers to pistols) with the little DAO guns and to become better accustomed to using +P in the "new" Airweights rated for a steady diet of +P loads.
It didn't take me long to suspect that the new Airlite/Airweight .357 Magnum models were really pushing the further boundaries of the human/machine interface in handguns. The .500 Magnums I fired were downright pleasant and enjoyable by comparison.
I remember thinking when I was younger, and an avid handloader, that an enjoyable afternoon was shooting several hundred rounds of stoutly loaded Magnum through various Ruger SA's (.357, .41, .44 & .45 Colt - "Ruger Only" loads in the older manuals).
I gave up doing the Magnum "shooting for thrill" thing after I was into my 40's.