Originally developed for military use, the 5.56 NATO cartridge is the high‑pressure cousin of the .223 Remington. It operates at roughly 58,000 psi versus the .223’s 55,000 psi and uses a chamber throat 0.125″ longer, allowing more powder for higher performance. This extra pressure yields slightly higher velocities and energies compared with .223, with typical 55‑grain loads around 3,130 ft/s muzzle velocity and a flatter trajectory downrange. Due to these differences, firing 5.56 NATO ammo in a .223 chamber is unsafe, whereas .223 can generally be fired safely in a 5.56 NATO chamber.
Our lineup of 5.56 NATO rifles features proven platforms for tactical and sporting use. Models such as the RF‑15 with a 16″ M‑LOK handguard and B5 stock offer an affordable entry into the AR‑15 world. Premium options from Daniel Defense include the DDM4 M4A1 RIII (14.5″) and DD4 RIII (16″) for home defense or duty use, while the DDM4 V7 Pro with an 18″ barrel and the lightweight V7 SLW deliver competition‑ready performance. Stag Arms’ 3‑Gun RH 16″ 223 Wylde and Smith & Wesson’s M&P Sport III provide reliable semi‑automatic operation and 30‑ or 32‑round magazines for extended sessions. Each rifle is engineered for accuracy, reliability and modularity, making them ideal for defensive training, competition shooting and recreational plinking.
To complete your 5.56 NATO setup, explore our extensive selection of optics, red‑dot sights, scope mounts, magazines and rifle slings to personalize your platform. For variety, consider other calibers like .223 Rem (safe to shoot in 5.56 chambers), 300 AAC Blackout for suppressed shooting, or 7.62 NATO when additional stopping power is required. You’ll also find rimfire rifles in 22 LR or 17 HMR for inexpensive practice, along with training classes to hone your tactical skills. Our experts at Frontier Justice are ready to help you find the right rifle and accessories to suit your shooting goals.
