What Happens If You Chamber 300 AAC In a 556 Upper

I accidentally chambered a 300 AAC in my 556 upper. This is what happened use code “tacticaladvisor“ to save on your order from companies below. - Vertx - 25% off - Cloud Defensive - 10% off - TA Target’s - 10% off - Neomag - 10% off - Grey Man Tactical - 10% off - Ace Link Armor - 10% off / Free Shipping - Lox Hair product - 10% off - South West Precision - 10% off - Premier Body Armor - 10% off - Cool Fire Trainer - “TACTICALADVISOR“ - Slate Black - “tacadv“