Just about to finish my first build which was an entry level knock around 16 inch 5.56. I'm just waiting for the barrel to come in. Because of the uber wait times on everything I've decided to get started early on my next build. Gonna go the SBR route an was interested in playing with a fun caliber. Seeing as how a SBR would be mainly for CQC, what's a nice big caliber that would perform well in CQC situations but still be useable in an AR build? Any suggestions welcome.