Josh, no Sir. 300Blk is a 30 Caliber Round and 5.56/.223 are 22 Caliber. All you would need my man is a 5.56 Upper to attach to this lower as the lower is universal to both calibers.

DO NOT TRY TO USE 223 OR 5.56 NATO ammo in this gun it is chambered for 300 blackout ammo , also known as 7.62Ã—35mm

Josh, No, this firearm is a 300 blackout firearm not .223/5.56 firearm. Barrel and chamber are much larger for the 7.62 diameter round. 5.56 diameter would be dangerous to fire from that dimension chamber and barrel.

No Josh, this is a 300 Blackout model ..chambered in 300 Blackout, it only functions with 300 Blackout ammunition (AKA 300 AAC) Can't use 223 or 5.56 in this one.

ATI Omni Hybrid P4 ATIGOMX300P4B

Name: ATI Omni Hybrid P4 ATIGOMX300P4B
SKU: 43052
Rating: 4.9 (10 reviews)

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10 Reviews

MSRP:

$275.78

Used Price:

$275.78

Sale Price:

$306.42

ATI Omni Hybrid P4 ATIGOMX300P4B Gun Stats

ATI Omni Hybrid P4

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Our OMNI HYBRID P4 features a fully-patented metal reinforced polymer upper receiver along with a fully-patented metal reinforced polymer lower receiver. The Omni Hybrid lower features a patented hammer and trigger pin retainment system, preventing movement from the hammer and trigger pin during firing. The Omni Hybrid also features our patented over-molded metal inserts, which reinforce the buffer tube housing and rear takedown pin as well as reinforce the front take down pins. This allows for metal-on-metal contact with both the buffer tube as well as the rear takedown pin thus increasing strength and durability from recoil and consistent firing. Specifications: Rail: 7" Keymod Free Float Gas Block: Low Profile Rate-of-Twist: 1:8" Pistol Brace 8.5" 1:8 Twist Nitride 300 Blackout Â Barrel