Hi Warren and welcome. It will fire 5.56 and .223 no issue. keltecweapons.com/firearm/rifles/su16/#:~:text=Like%20all%20the%20SU16%20models,require%20a%20lightweight%2C%20compact%20rifle. ------------- Cheers, stay safe and happy holidays!

yes it is from keltec see ***** "SU16A™
KelTec is where the modern Sport Utility rifle was reinvented and the SU16A is where it all began. *******Chambered in 5.56 NATO keltecweapons.com/firearm/rifles/su16/

Hi Warren, yes sir, this gun is rated for 5.56, Bud's should have that in the listing >>> keltecweapons.com/firearm/rifles/su16/
Stay safe & have a great day!

Yes, it can shoot 5.56.
KelTec is where the modern Sport Utility rifle was reinvented and the SU16A is where it all began. Chambered in 5.56 NATO, it's the go-anywhere utility rifle. It features a magazine storage stock that holds two proprietary 10-round magazines. The forend covers an 18.5" barrel and doubles as a bipod. Although the SU16 models come with adjustable sights, the receiver offers an integrated Picatinny-style rail for mounting an optic.