My wife & I, together, have (8) Bersas, .22LR up through the UC45. Wouldn't trade/sell any of them & have 3 more on my wish list. What do you need to know about them?
The Thunder .22LR prefers HV ammo. Some Thunder .380s are ammo picky until broken in, but our two weren't. Break-in for my 9mm's, .40S&W & .45 consisted of clean, lube & load - there, broken in.
My .32 cal. had a couple of stove pipes in the first 50 rounds, that's it. I'd say the two 9mm's are the sweetest shooting of the bunch with the .45 a close second.
I wish I was a good shot, but from a rest, they are dead on accurate.