I submit my opinion that a .380 ACP pistol is a 'minimum' caliber, despite the info put forth that a .25 ACP is 'adequate'.
Also my opinion.
I think the 380 can get most jobs done. Shoot a 95 grain HP in some wet soil and see a nice hole. Lot more dirt flying than a 22.
The ole dirt flying test
Even works with new dirt...
I like my basic LCP 380. I can keep it in my pocket. My small but bigger Ruger LC9s 9mm, not so much...
Both are capable belly-poppers, but the LC9s is a surprisingly accurate midget pistol.
