BudsGunShop.com - Is the barrel stamped 5.56?

Yes this is a 5.56/.223 rifle. The 5.56 and the .223 are the same case but the difference lies in how the chambers are cut. The .223 chambers are usually cut with less lead so the 5.56 bullets may hit the rifling and cause pressures to spike. The 5.56 chamber will fire both and that's what this rifle has.

Hi Brian, Yes 5.56mm NATO caliber (accepts .223 Remington) Specs - Smith & Wesson Military & Police 15 Sport II Magpul MOE M-LOK 10305
AR-15 Semi Automatic Rifle
Direct Gas Impingement
5.56mm NATO caliber (accepts .223 Remington)
16" B4140 Steel Barrel
1:9" Twist
M4 feed ramps
7075 T6 Aluminum upper and lower receivers
Mil spec hard coat anodized black
Adjustable A2 front sight post
Magpul MBUS folding rear sight
6 Position telescopic stock
Magpul MOE Carbine Length M-LOK Hand Guard
Chromed Gas key and bolt carrier
30 round magazine
Overall length 36.8" Extended / 32" Collapsed
Overall weight 6.45 lbs
Made in the USA
Matte Black