We are not against training with 5.56mm/.223 rounds as much as possible, but a question arises in these cash-strapped days: If it comes down to training or not training, or limiting the rounds fired, can we learn and substitute a 9mm carbine based on the AR platform for the larger rifle rounds?
Does it translate to shooting the 5.56mm/.223? The short answer is yes, and the Rock River Arms (RRA) LAR-9 is up to the task.
Easily Convert Your .223 AR Into Reliable Shooting 9mm
Sub-caliber upper assemblies allow fast and simple conversion of ARs chambered in .223 to 9mm Luger. True, dedicated, complete upper receivers are assembled from military specification components; includes a Wilson, 1-10 twist barrel, bolt and carrier, charging handle, shell deflector, heat-shield lined handguards, sling swivel, and A1-style flash hider.
Additional items not included but required for conversion to 9mm are a 9mm magazine AND magazine adapter, action spring, and recoil buffer.