I've long been very interested in the storied debate, discussion and opinions on 125 grain .357 Magnum ammo in revolvers... K-frames specifically, where the grand debate was born.
In taking a lot of great discussion in, I've come to a conclusion-- maybe my conclusion will help your position.*
Due to the length of the 125 grain bullet and the colossal fireworks that often follow it, there is no revolver with attendant cylinder gap/forcing cone that won't be accepting stress from these loads. Certainly... a big, massive, meaty monster of a revolver will resist this abuse more than will a dainty one, but it will not stop the abuse that's being dished out. A Freedom Arms single action, an N-frame S&W or one of the short-printed Ruger Redhawk revolvers will resist the beating more than others, perhaps, but will still be subjected to it.
So I've come to accept that and run with it. I don't run full-bore 125gr Magnum loads in my Model 19. Admittedly, I don't even like to run them in my L-frame 686. But I do have a Taurus Model 66 that I will beat without mercy, because it's a low-dollar revolver and for what I've got in it (monetarily and emotionally
), I think it came to me for the select purpose of throwing a beating down on it.
Which is fun, because the darn thing is VERY accurate so it's fun to beat upon.
I don't have one of the three BIG revolvers I mentioned above. If I did...I wouldn't put hot 125's through them, either. However, that's because 95% of the handguns I own are -NOT- tools. They are much adored "toys." If I were carrying a .357 Mag revolver for defense...that would be a tool and I would use it as a tool. And if 125gr loads were called for, that's
what I'd feed it.
Also keep in mind that while S&W quit making K-frame magnums (perhaps due to this?), they continue to make J-frame magnums. They don't think you'll kill many J-frames with hot 125's, so I think most any .357 Magnum will take a lot of hot 125's before it goes in the crapper.
*correction: this conclusion was served up for me and it "fit" so I've adopted it. I didn't come up with it on my own.