The APC300 shares all the same dialed-in ergonomics, handling and modularity features and benefits that has made the APC9 so popular but chambered in the versatile 300BLK cartridge. The benefits of being able to fire both super and subsonic loads of differing energy levels, suppressed and unsuppressed did not come without some engineering challenges along the way. The APC300 features an adjustable gas valve positioned forward of the handguard, allowing the user to select the amount of gas introduced into the system, making the platform easily tunable for ammo/suppressor combinations. Given the similarities in size, weight, and ergonomics between the APC300 and APC223/556 platforms, many customers utilize the latter as training weapons and reserve the APC300 as an operational weapon. This saves the customer a substantial amount of money given the cost of specialized 300BLK ammunition.