EXCLUSIVE

Kim Zolciak‘s little girl is now a grown ass, pistol-packing mama, and her mom wouldn’t have it any other way … TMZ has learned.

Brielle Biermann turned 21 on Sunday, and when she got home on Monday … Kim was waiting with her gift — a brand new customized Glock 43, complete with rose gold slide. Brielle seemed a little nervous around the weapon at first, but Kim said it’s important for her to have it … now that Brielle’s living in her own condo.  

We’re told Brielle’s practiced at a gun range before. She doesn’t have a license yet, but Georgia doesn’t require one if it’s stored in a home, car or place of business.

BB also got some pieces of art, which look like molds of topless women, and set Kim back $5,550 each! The handgun was a relative bargain at just $1,300.

While there’s, rightfully so, a lot of talk about gun control these days … that debate’s focused on assault weapons like the AR-15, not Glocks.