Is this type of ammo good for SD? In my area is all I could find for now is fiocchi 357 mag 158gr. Some people tell me is going to penetrate too much and not dump the energy on the assailant other tells me is the best I could get to ruing someones day.

Just in case is gonna be fired from a GP100 6inch barrel.

I would say yes.

+1

Txl

6 inch should get that load moving pretty well, I would think it will be pretty effective.

I would be happy with that load, especially out of your 6" GP100.

My favorite president once said, "Trust, but verify".  I believe this is a good way to choose ammunition.

As hard as it is for an old timer like me to believe, the best SD ammunition development is not being done in .357 Magnum.

Now obviously, anything the 9mm can do, the .357 can also, but there is just enough difference between the 2 cartridges that the good SD 9m bullets simply can't be loaded into .357 Mag cases.  Various barrel lengths also complicate the issue.

Many of the lightweight JHPs for the .357 actually under-penetrate.  Many of the heavier JHPs and JSPs over-penetrate.

You could try some on a row of orange juice boxes filled with water.  Not the most scientific test in the world, but far from the least.

If it expands in water, there is a good chance it will expand in real life.  No guarantees however.

An 158 grain bullet probably won't under-penetrate.  If it expands and makes it through 3 OJ cartons, and into the 4th one, trying hard to make it into the 5th one, it is probably, (but not necessarily), a good SD load.

Gelatin tests would be better of course, but are a bit expensive and complicated for the casual experimenter.

thank you for all the good advice I will definitely try the OJ carton or water jugs just to make sure. To understand this question and why I ask this maybe I have to give the background story. And maybe I could get extra advice who knows. I live in P.R. and crime is rampant, you could get killed by doing anything. I live in an area where the people who live there is mostly elderly which make them more prone to robbery, assault and home invasion. I bought this revolver SS for my grandmother because you cant see a black glock, ppq or shield on the table at night. So SS is much easier for her to see. I arrive late at night because of work so she is alone at home most of the night.

To put things into context (and if you understand spanish) you just have to read this newspaper, this happened just 2 days ago. I just want to give her the opportunity to defend herself

http://elvocero.com/vil-ataque-a-la-morada-familiar/

Some TruGlo TFO sights will make it very easy to locate that weapon and it's sights in the dark.

Good looking revolver.

Get some .38 special loads for your Grandma.  

A full power .357 magnum load, even in that heavy of a gun won't be fun for someone not used to shooting.

I prefer a bonded 180gn JHP for .357 mag.

Probably. This one did very well from both a carbine and a revolver:

https://www.youtube.com/watch?v=CzrxHjX7eWo

exposed lead hollow points work very well, main reasons you don't seem them as often is IIRC because semi autos tend not to like them. Since most defensive ammo is designed around semi autos, many revolver rounds will be carry overs.

Your Fiocchi ammo is fine. Grand Ma: make sure she can hold and fire the revolver. Get a box of 38 Special so she can practice. *** Absolutely make sure she has the mindset to use the weapon.***  Do not rely on the bad guys being scared by the seeing the weapon in hand.

I'd go Remington or Federal 125 grainers at 1450 fps.    These loads are equivalent and have a good reputation.

Based on what?  Other than your opinion of sorts of course.

Don't you read the Armed Citizen column? Old people are the Grim fucking Reaper, man.

The One Shot Stop data that everybody gets fired up about claims that this is the best load.    I'm somewhat skeptical about all that, but careful consideration will reveal that my statements are correct:

1.  The loads are equivalent.  (They both feature a 125 grain JHP going the same velocity.)
2.  They both have a good reputation.  (Google and see.)

Yes. Probably the best column in AR. Always gives me that "Hell Yeah!!" feeling, I have a soft spot for the elderly. My own Mother(75) is now carrying a J-frame because of hand strength, previously carried G19.  

125gr. is best for SD. Use a copper bullet for penetration.

Cor-Bon DPX 125gr. is a good choice.

They have a great reputation. That reputation is usually based on folk lore and legend rather than science though. Even from a 4" bbl the 125Gn SJHP loads often under penetrate.

When Doctor Roberts tested .357 Magnum ammunition the Winchester 180 gn Partition Gold was the best performing load. It is however no longer produced by Winchester.