Shooting lead bullets through the stock barrel is fine. I been doing it for 14 years in the Glock. I use mostly hard cast that run 18 to 21 bhn (hardness) and have NEVER had an issue with this, and I shoot a ton of lead, far more than jacketed, cause i hand load.
Get an AM barrel if ya want to save brass life, but it ain't needed to shoot lead. Again, I shoot 200gr Hard cast through the G20 stock barrel, and accuracy is plenty good even at 100yds for Texas deer.
BB makes a good "factory round" if ya want quality factory loaded bullets, go with BB. Just don't use them for human SD loads... They are NOT for SD on humans !
Even in the 9mm, a Hard Cast bullet will go through several folks, not for human SD.... ! not in a populated area for sure..
You boy's saddled this bronc, now let's see if you can ride it.
Jesus said: You who are without sin cast the first stone
.. John 8: 7