Like the larger M-10, the M-11 has open sights with the rear pinhole sight welded to the receiver. These sights are for use with the folding stock, as using them without the stock is nearly useless because of the initial jump of the weapon due to its heavy, open-bolt design. The M-11A1 also has two safety features which are also found on the Model 10A1. The charging handle rotates to 90 degrees to lock the bolt in the forward position thus preventing the weapon from being cocked. The second safety is a slider which is pushed forward to lock the trigger, which in turn pins the bolt to the rear (cocked) position. This prevents the weapon from discharging even when dropped, which is not uncommon with an open-bolt design.
The rate of fire of the M-11A1 is one of the biggest complaints on the firearm. Listed as approximately 1,200 rpm (rounds per minute), the MAC-11 is capable of emptying the entire 32-round magazine in less than two seconds, which many users view as a drawback. Rate of fire will also vary depending on the weight of bullets used. The gun also has a selector switch that allows it to fire only one round at a time in the semi-automatic mode.
Noting the weapon’s poor accuracy, in the 1970s International Association of Police Chiefs weapons researcher David Steele described the MAC series as “fit only for combat in a phone booth.”
The M-11 is the least common version in the MAC family of firearms. At the MAC-11’s high cyclic rate, extreme trigger discipline is required to discharge short bursts, which are required for combat effectiveness. Without proper training, the natural tendency of the inexperienced shooter is to hold down the trigger, discharging the entire magazine in little more than two seconds, often with poor accuracy due to recoil.
A specific suppressor was developed for the MAC-11, which used wipes as baffles, instead of the reflex baffles that Mitchell Werbell III created for the MAC-10. Though wipes are less durable than reflex baffles, they had the advantage of proving quieter for the MAC-11. The suppressor is 224 mm in length and is covered with Nomex-A heat-resistant material.