Underwood makes some very hot .380 ammo, I also have a video where I tested the same ammo in a Taurus TCP which is the same size as a LCP or P3AT.
90gr Bullet at 1250 FPS = 312 ft lbs of energy
115gr bullet at 1150 FPS = 337 ft lbs of energy
That puts these .380 rounds real close to a 9mm
A all steel gun like this can handle the extra energy but I am not sure if they shoot accurately, I will do a test in the future with this gun.
They did not shoot very accurate out of my Taurus TCP or I was not able to shoot them as accurate as a Speer gold Dot.
Watch video Testing 380 ACP Underwood Ammo In The CZ83 3.8 Inch Barrel online without registration, duration hours minute second in high quality. This video was added by user Our Tennessee HomeStead 17 September 2013, don't forget to share it with your friends and acquaintances, it has been viewed on our site 13,290 once and liked it 47 people.