I've posted much of this info in another thread, but since I've never seen it anywhere else, I'm using it in a new post. If this is improper, I apologize, and have no problem with the mods deleting it.
I've reloaded hundreds of .357 caliber Berry Bullets, both 125 grain flat point and 158 HP. I also use Rainers, and anything I say here may apply to both brands.
In my opinion- and this is strictly an opinion - the 158 grain hollow point Berry Bullet going 900 - 1,100 fps could be a devastating self defense load. The small hollow point even has a little "pin" in the center, similar to that on Federal's Hydra-Shok. I assume this "pin" could increase expansion.
And since plated bullets are very soft, and there is no jacket to shed, it seems bullet deformation/expansion is ensured - but that's just an opinion.
The 125 grain is my wife's favorite practice load. Since I do all the gun cleaning, the cleanliness is what I like.
I push these plated bullets (both 125 and 158 grains) at about 1,000 - 1,100 fps (Using a F-1 Shooting Chrony) with 7.3 gr. of Herco using .38 special cases in 4" .357 magnum revolvers. I use standard small pistol primers - NOT magnum primers.
I also use a loading of 7.3 grains of Herco in strong revolvers, specifically my modified Ruger Service Six and the wife's S&W Model 13, again using .38 special brass.
Ruger Service Six w/3" barrel, bobbed hammer, trigger job, etc.
The report and recoil is similar to a light .357 magnum, and I've noticed no damage to the cases. I've actually gone as high as 8.5 grains of Herco with no ill effects.
For a .38 special revolver, I reduce the load to 6.8 grains of Herco which chronys around 930 fps. I believe such a load would be very effective when fired from a .38 special. The pressures do not seem high, and I don't believe it would damage a well made .38.
I like this load because it is extremely clean. I used Unique for many years (like everyone else), but I switched to Herco because it is so much cleaner.
Here's the rub: I use a Lee turret press. If I do not use a 4 die set when reloading plated bullets, I have trouble unloading the fired cases. The use of the fourth die, the optional crimping die, eliminated the problem of hard to eject empties. Plated bullets are very soft, and the crimping die sizes them just right.
Be careful when sizing plated bullets. The plating is thin, and easily damaged.
One more thing about Berry Bullets: I've noticed a huge variation in FPS with plated bullets, up to 100 fps difference between rounds. I don't see this much variation with jacketed or lead bullets I reload.
Sorry for the long post, but like I said, there does not seem to be a lot of info out there from those who actually used plated bullets.