MANUFACTURER – Military Armament Corporation (MAC), Marietta, Georgia
STATUS – Obsolete
SERVICE – Commercial sales to military and other customers
The M10 suppressors follow the standard two-stage Sionics (Studies In the Operational Negation of Insurgents and Counter-Subversion) design with the addition of a flexible muzzle wipe. The basic design was patented by Mitch Werbell III in 1968 as a “Firearms Silencer with Helical Suppressor Elements.” The patent was the basis of his suppressors used on M16 and M14 rifles in Vietnam and was adapted to the suppressors used on the Ingram M10 submachinegun.
The rear tube of the suppressor was 9.5 cm (3.75 in) long and 5.4 cm (2.125 in) in diameter and acted as the primary expansion chamber. The center piece of the rear assembly was the sleeve that threaded onto the submachineguns barrel and held the rear assembly together. The sleeve fit over the muzzle and short section of barrel, screwing on to the 7/8 x 9 NC threads. The font portion of the sleeve was threaded to fit into the bushing that closed off the front of the expansion chamber. The front of the bushing was threaded to accept the front tube. Within the threaded porting were twelve 4.7 mm (0.1875 in) holes around the central port of the bushing. These holes would allow the propellant gases to bleed into the front tube assembly.
On the central tube of the sleeve in the rear expansion chamber were 4 rows of five 4.7mm (0.1875 in) holes that allowed the initial muzzle blast of propellant gases to pass into the expansion chamber. Within the expansion chamber, filling the space between the sleeve and outer tube, were dozens of aluminum eyelets or grommets. These eyelets caused the propellant gases to move in a random motion, expending energy and being cooled from contact with the aluminum eyelets. It is one of the more unusual aspects of the Sionics suppressor, but the eyelets worked with surprising efficiency.
The front tube contained the additional suppressor components and was 17.8 cm (7 in) long and 4.1 cm (1.625 in) in diameter. With the front tube screwed down onto the bushing connecting the two stages of the suppressor, the incoming propellant gases stuck a series of components, all intended to slow and cool them before they reached the muzzle. The first encounter of the gases was with a single large conical baffle. The central cone of the baffle faced back towards the muzzle of the weapon, it would guide the gases coming through the bleed holes around the circumference of the bushing, allowing them to expand before being forced back into the bore of the suppressor. The next component to block the gases was an aluminum right-hand spiral diffuser. This was built much like a large-flanged screw around a perforated central post. In the post at the base of each flange were four evenly spaced out 3.2mm (0.125 in) holes into the central support. The holes allowed the incoming propellant gases to bleed out into the flanges, forcing them to spiral to the right and cool from their contact with the aluminum. A second spiral diffuser was stacked next in the front tube assembly, but this diffuser had a left-hand twist, the reverse of the other component.
The baffle at the rear of the front tube and the two spiral diffusers stacked onto it, were held in place by an encapsulator, a threaded plug with a central hole for the passage of the projectile. This plug was threaded down into the tube with the use of a special wrench. The original encapsulator was a solid metal piece, but these were replaced with a multiple-component encapsulator.
The new encapsulator included a centrally perforated solid neoprene wipe. This wipe was held in place by the encapsulator being screwed down onto the spiral diffuser stack. The replaceable end cap assembly sealed off the front of the suppressor. Within the end cap were an additional pair of solid neoprene wipes with central holes. The wipes were spaced out from each other by a central spacer tube. Originally a snap ring was used to keep the end cap assembly together. With the end cap assembly threaded into the muzzle of the front tube, the suppressor assembly was complete.
In use, the suppressor was screwed down solidly over the muzzle of the weapon. In use, the propellant gases following the projectile would first enter the rear tube by expanding through the ports. Inside the expansion tube, the gases would initially slow and be cooled by passing around and through the eyelets. Passing into the front tube, the gases would be deflected by the baffle before entering the spiral diffuser stack. Finally, the projectile would pass through the flexible plastic disks in the encapsulator, and finally the end cap assembly. The disks would wear from use and needed to be replaced every few hundred rounds for maximum efficiency. The simplest manner of replacing the wipe was just screwing on a new excapsulator and end cap assembly when the suppressor was disassembled for cleaning. The cooling propellant gases coated all internal components with carbon, another reason for regular maintenance.
