need some ideas

[Oneslickbooger]

I have a extra set of an upper and lower sitting around ready for something. I have a couple AR's chambered in 5.56/223 one in 300blk and one in 7.62x39.
What caliber should I build next. I was thinking about a 22 pistol for the kids but still up in the air. Want to hear what some of you think.

[Eric]

SBR in a pistol caliber