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Arsenal Blog 005: American-180

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Arsenal Blog 005: American-180

Arsenal Blog 005: American-180

SILENCERCO’S ARSENAL SERIES showcases guns we love for various reasons that reside in our in-house arsenal. We are best-known for making guns quiet in order to do this, we must interact with a great variety of amazing platforms. In these posts we will tell you about each platform we like, why it’s different and relevant, and why we think it belongs in our pantheon of greatness.

The American-180 is an Austrian-made, blowback open bolt submachine gun chambered in .22 LR and is fed from a spring-loaded, top-mounted drum magazine.

The original concept for the American-180 came from a man named Richard Casull and was based off of his Casull Model 290. The Casull Model 290 was developed 10 years prior to the American-180 and was not well received when released, with reports of only 80 firearms being sold. The American-180 was then developed in the United States in the 1970’s.

American 180 magazine

One of the notable features of the American-180 is its ability to deliver an extremely high rate of fire with minimal recoil; when chambered in .22 LR, the American-180’s rate of fire reaches 1,500 rounds per minute. Some models are chambered in .22 short magnum (manufactured by ILARCO), and these models achieve a cyclic rate of 1,800 rounds per minute. This .22 rimfire cartridge achieves muzzle velocities similar to .22 magnum but uses a case length similar to .22 LR and launches a 40gr projectile at 1,350 FPS with 160 ft. lbs. of muzzle energy. All of this translates to the American-180 producing 2,400 ft. lbs. of energy per second with controllable full-auto fire.

Manufacturer literature states that the American-180 is capable of placing 165 rounds – the entire magazine – into a 3-inch circle at twenty yards in three seconds. This rate of fire and controllability produces a swarm of 40gr .22 caliber projectiles which can prove devastating to soft targets as well as cinder block walls, glass, car doors, and brick. These features made the American-180 suitable for service in State and Federal penitentiaries as a tool for crowd control, as well as for police and SWAT patrol rifles.

One account of the American-180’s capable firepower comes from Police Officer Gary P. Jones from Fort Lauderdale, Florida when he was involved in an active shooting in November of 1974. Officers Jones and his partner, Officer Mike Gilo, were involved in a shooting with two suspects in a Camaro. As the suspects in the Camaro made an attempt to evade the police, the suspect in the passenger seat fired at the officers. Officer Gilo fired approximately 40 rounds through the back window of the Camaro with his American-180. Officer Jones then fired his 12 gauge shotgun, but was unable to connect with his targets. Reports state that the Camaro was found shortly after with the passenger dead in the front seat due to multiple .22 projectiles in his body. The driver had fled the vehicle but was later taken into custody and treated for multiple .22 caliber gunshot wounds.

The remarkable rate of fire that the American-180 can achieve would be pointless if not accompanied by a very high capacity magazine. The American-180 uses a drum magazine that is mounted on top of the gun, much like the World War I-era Lewis gun. The drum magazine on the American-180 uses a wind-up spring to feed the rounds through the magazine and into the feed lips.

The Spectre II, American 180.

The early prototype magazines had a capacity of 180 rounds, which is where the American-180 gets its name. This capacity was later changed to 177 for original production models, with 275 round magazines also produced and made available for purchase. Depending on the magazine, the shooter could fire 35 five-round bursts with a 177 round magazine or 55 five-round bursts with a 275 round magazine. Firing the American-180 in five-round bursts enabled the user to attain greater accuracy and conserve ammunition for the greatest amount of time.

While in production, the American-180 had multiple barrel lengths ranging from 9 to 18, designed to meet an operator’s individual needs, which were easily interchangeable due to the American-180’s design.

The receiver features a large captive thumbscrew located on the underside of the receiver and in front of the trigger guard. This screw passes through the receiver and screws into the tenon of the barrel. Forward of the thumbscrew, there is a square pin that passes through the receiver acting as the recoil lug. The barrel has a matching recess cut into its underside that interfaces with this recoil lug. This design is an effective way to maintain correct headspace and alignment of the barrel to the bolt-face without breaking the bank.

One of the American-180’s great design features is the ability to mount a Laser-Lok sight. The SC-100, made by Laser-Lok, is a helium-neon gas laser which had an effective range of 150 meters at night with a battery capable operating the laser for two hours of uninterrupted use. The SC-100 also has the ability to be plugged into a power source to allow the user unlimited uninterrupted use of the laser.

The American-180 fires from an open bolt to insure reliable ignition of the rimfire cartridges.  Using a cartridge like .22 long rifle and .22 short magnum in a full-auto platform requires some design changes in order to make the gun fire. Like most firearms using a low pressure cartridge, the bolt does not lock closed but is held closed against the breech by the recoil spring.  

This is an effective design for semi-automatic guns, but with a full-auto platform, the non-locking bolt creates an unreliable ignition due to an issue known as bolt bounce.  As the bolt closes and hits the breech, the bolt will bounce back off the breech face for a miniscule amount of time. During this miniscule amount of time, the hammer will strike the firing pin. With the rearward motion of the bolt and forward motion of the firing pin and hammer, the two opposite motions reduce the force applied to the rim of the cartridge, which in turn will fail to fire the round.

With an open bolt design, the firing pin is fixed to the bolt face. Pulling the trigger releases the bolt allowing it to move forward. As the cartridge becomes fully chambered, the firing pin attached to the bolt will continue to move forward igniting the primer and firing the round.

Things We Like

Comb Height of Stock Allows for Good Cheek Weld: With the drum magazine on top of the rifle, the sights on the American-180 need to be designed high enough to clear the magazine. Raised sights require that the comb height on the butt stock be the proper height to allow for a comfortable cheek weld and not a chin weld. The designers of the American-180 made sure to design the stock to allow for a nice cheek weld while aiming. This is accomplished by having the stock butt up against the back of the receiver, not the underside of the receiver, like the Thompson SMG. This gives the stock a more natural profile without having a large riser to raise the comb height.

Self Cleaning Bolt: In order to improve reliability of the American-180, the bolt has multiple channels cut into the sides to allow debris and fouling to be removed from the bearing surfaces of the bolt. The channels are cut at a diagonal angle on the bolt’s left and right surfaces. The effectiveness of these serrations is evident after only a few dozen rounds.

Modularity: As stated above, the Amercian-180 features an effective and simple way to change out the barrel to whatever the operator needs or wants, and can accommodate a full-size 18 barrels down to a 9 SBR barrel. Besides having a quick change barrel, the buttstock is also easily removable and is attached using a dovetail channel and a push- button latch to lock into into place. To remove the buttstock, the user simply pushes the button, which is located on top of the stock adjacent to the back of the receiver, and then pulls the stock back. With the stock removed and the short 9 barrel in place, the rifle becomes very compact, maneuverable, and deployable in tight spaces such as a vehicle. In its longest configuration, excellent precision, accuracy, and controllability are achieved.

Loading and Unloading Ergonomics: The user controls for loading and unloading the American-180 work well, even with the difficulty of having a large drum magazine on top of the rifle. The drum magazine sits over the front part of the receiver where the forward section of the bolt reciprocates; this is where the charging handle would reside on a common .22 rifle. To overcome the ergonomic disaster from a lack of clearance to grip the charging handle putting it in the usual place would cause, the charging handle on the American-180 has been moved to the rear of the receiver. Interfaced with the rear portion of the bolt on the left-hand side, the charging handle is non-reciprocating and easy-to-access. The magazine catch is located directly above the charging handle on top of the receiver; this location allows the user to insert the magazine with his support hand and operate the magazine catch at the same time to lock the magazine into place and then quickly transition to pull the charging handle to the rear, chambering a round.

Things We Don’t Like

Lack of Reliability with Subsonic Ammunition: Shooting subsonic ammunition while using a silenced firearm really enhances the whole shooting suppressed experience, especially in a cartridge like .22 LR. Unfortunately, the American-180 does not function well with subsonic ammunition. The recoil spring on the American-180 is fairly stout and requires significantly more energy to move the bolt. Subsonic .22 ammunition has 30 – 50% less energy than high velocity .22 ammo. This extra energy allows the bolt to travel all the way to the rear, storing enough energy in the recoil spring to then strip and chamber the next cartridge. Without the high velocity ammo, failures to feed are a frequent occurrence.

The Spectre II, American 180.

Drum Magazines Take a Long Time to Load: The American-180’s drum magazine has the advantage of providing an enormous capacity, but that capacity comes at a cost. The drum magazine has 55 columns that follow the circumference of the drum. Depending on the capacity, up to five rounds can be stacked in each column with the projectiles facing inward. The magazine has incremental vertically placed fins on the outer and inner perimeters to form these 55 columns and hold the rounds in a tidy fashion. To load the magazine, the user must place a single round in the correct orientation on the feed ramp of the magazine, then rotate the base plate to allow the round to fall into its column. Often, while rotating the base plate, the rounds will become crooked and miss the column and become jammed. The user must then un-jam the round and start again.

Top Mounted Magazine Obstructs Sight Picture and Peripheral Vision: With the drum magazine mounted on top of the rifle – an area that would normally be clear of any object in order to allow the operator to see around his iron sight – it obstructs the shooter’s sights. Unfortunately, the iron sights are not tall enough to achieve a proper sight picture on target with the 275 round magazine. The top of the magazine is visible in the bottom third of the rear aperture and the front sight post barely clears the top of the magazine. Anything below the 3 or 9 o’clock positions outside of the aperture sight is blocked by the magazine, making transitions from a high to low targets difficult and decreasing the user’s ability to see below his intended target.

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