A few thoughts:
1) .380 ACP takes a big velocity hit short barrels, far more so than 9mm Luger (and .32 ACP is even more barrel length sensitive.
That means the performance of any specific hollow point in a 2.75” barrel will almost always be a lot different than the same load in a 3.5” or 3.9” barrel.
2) Velocity matters as most hollow points have a fairly narrow velocity range in which they will expand and achieve adequate penetration. Too slow and they will not expand. Too fast and they will expand too soon and or over expand and under penetrate.
3) It matters a lot more in the .380 ACP as it’s a marginal cartridge that struggles to both expand and penetrate.
4) Most shooters who swear by a particular load often have no idea what that load actually does in their .380 ACP pistol and way too many of them are working with some very inaccurate assumptions.
5) Some shooters place way too much faith in the FBI minimum penetration numbers.
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Putting some of those points together with my own ballistic test results.
Here we are getting right around 13” penetration with a PPK/S and a 3.5” barrel with a 90 gr XTP with a muzzle velocity around 1050 fps.
Expansion isn’t impressive by add hype standards but that’s what you can expect in a .380 ACP of you also want 12 minimum penetration.
Here is the same load from a 2.75” Kimber Micro. It’s penetrating about 11.5” with a muzzle velocity of 990 fps.
I had to work to get ballistic performance in a 2.75” barrel. Any slower and it won’t consistently expand. As it is, I am not going to worry about it being 1/2” short of the 12” FBI minimum.
That minimum is based on agents shooting at fleeing felons, and or from the side and or other aspect ratios other than face to face. If you as an armed citizen is shooting at someone who is fleeing and or not facing you, you will have far bigger problems than bullet performance, such as being able to justify the person you shot was an imminent threat.
This is a “hard cast” bullet. Note the excessive penetration. None the less the “hard cast” crowd and the similar FMJ crowd avoid hollow points due to fears that they will fail to reliably expand.
That’s not a valid fear as if a hollow bullet fails to expand it just a a like an FMJ.
A valid concern is that they may over expand and under penetrate. These are not .380 ACP but rather 9mm FTX bullets fired from a CZ 75 Compact PCR. Note the 10-11” penetration when fired from the 3.75” barrel of the CZ Compact. It’s not bad, but it’s at the low end of what you want. From a shorter 3.1” barrel Kimber Micro they would probably be in the 12”-13” penetration range.
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My whole point here is that FTX bullets in pretty much every cartridge they are loaded in are a strictly short barrel load, and will consistently under penetrate down in the 7-8” range in a 4”-5” barrel.
For longer barrel .380 ACPs the 90 gr XTP is a better choice.
The Remington 102 gr Golden Saber is also not bad in a 3.5 -4” barrel as it expands well and will give you 10-11” penetration.
So….do your own testing.
Failing that, look for test results in the same handgun or barrel length you use.
And if that’s not available, at least try to get some chronograph results to see what velocity you are really getting from the load in your hand gun to help make sure you are in the sweet spot.