While I think for civilian defense/concealed carry, the smaller calibers are not given their due, I think it is worth noting the challenges that face an ammunition maker that includes .380 acp in their lineup.
The bullet diameter while usually lighter, is the same diameter with roughly the same frontal area as 9mm Luger and 38 special. If you look at the room for propellant the .380 falls well short of 9mm and nowhere near the 38 special.
The nine which has been around seemingly forever would not have been practical without advancements in powder that were developed in its infancy. There would not have been enough case capacity for reasonable ballistics. Even today, developing a state of the art 9mm round can be a challenge. Look at the case displacement and then look at the pressure it takes to push the bullet to the desired velocity, especially in a short barrel because the highest pressure powder tends also to be the slower burning variety.
When you look at the .380acp case displacement by comparison, it will become clear that it presents even more of a challenge than the 9mm. This is compounded by the fact that .380 is increasingly popular in very compact guns with very short barrels.
While fast burning powders exist that will give the needed pressure, they have the potential to give such a fast pressure rise, that they can be quite hard on the less robust guns, increasingly popular in this caliber.
Case volume is also more critical with the fast burning powders. They can be very touchy in terms of bullet setback or even the smallest error in over charge in these tiny cartridges.
This is the primary reason that the .380 in jhp has so much trouble both making the 12 inches of penetration so popular today while at the same time opening properly. At lower velocity the jhp opens slower and is more likely to penetrate. The problem is the speed that is ideal for penetration tends to be very close to the point where most jhp don't open.
A better bullet design that more reliably opens at lower velocity puts you back with short penetration and you start chasing your tail.
A heavier bullet all else equal will penetrate more but all else is not equal because the heavier bullet will be even tougher to get up to speed and this goes double with a short barrel.
This is not to say jhp are not a good idea in .380 or even that one that meets the Jello dream of 12 inches in full bloom can not be made. It does mean that doing so is very difficult.
Meeting the same requirement in the larger calibers is a balancing act between bullet design, bullet weight, and pressure and with these rounds there is enough room for error in all three variables to insure a reasonable probabliity of success.
The bullet diameter while usually lighter, is the same diameter with roughly the same frontal area as 9mm Luger and 38 special. If you look at the room for propellant the .380 falls well short of 9mm and nowhere near the 38 special.
The nine which has been around seemingly forever would not have been practical without advancements in powder that were developed in its infancy. There would not have been enough case capacity for reasonable ballistics. Even today, developing a state of the art 9mm round can be a challenge. Look at the case displacement and then look at the pressure it takes to push the bullet to the desired velocity, especially in a short barrel because the highest pressure powder tends also to be the slower burning variety.
When you look at the .380acp case displacement by comparison, it will become clear that it presents even more of a challenge than the 9mm. This is compounded by the fact that .380 is increasingly popular in very compact guns with very short barrels.
While fast burning powders exist that will give the needed pressure, they have the potential to give such a fast pressure rise, that they can be quite hard on the less robust guns, increasingly popular in this caliber.
Case volume is also more critical with the fast burning powders. They can be very touchy in terms of bullet setback or even the smallest error in over charge in these tiny cartridges.
This is the primary reason that the .380 in jhp has so much trouble both making the 12 inches of penetration so popular today while at the same time opening properly. At lower velocity the jhp opens slower and is more likely to penetrate. The problem is the speed that is ideal for penetration tends to be very close to the point where most jhp don't open.
A better bullet design that more reliably opens at lower velocity puts you back with short penetration and you start chasing your tail.
A heavier bullet all else equal will penetrate more but all else is not equal because the heavier bullet will be even tougher to get up to speed and this goes double with a short barrel.
This is not to say jhp are not a good idea in .380 or even that one that meets the Jello dream of 12 inches in full bloom can not be made. It does mean that doing so is very difficult.
Meeting the same requirement in the larger calibers is a balancing act between bullet design, bullet weight, and pressure and with these rounds there is enough room for error in all three variables to insure a reasonable probabliity of success.