The new HK suppressed MR556A1-SD is equipped with
a cutting edge next generation of suppressor technology from Operators
Suppressor Systems Inc. (OSS). It is coupled with HK’s unique new
Modular Rail System (MRS) to provide the shooter with a high performance
integrated weapon system.
The modular rail system (MRS) for the MR556-SD allows the shooter to
place individual rail components and accessories anywhere along the
length of the seven free sides of the forearm using the slotted
HK has been working with OSS to develop the next generation of advanced
suppressors for the HK MR series of rifles and carbines.
These suppressors are comprised of two modules, a Back Pressure
Regulator (BPR) and a Signature Reduction Module (SRM)™. The BPR1425™
on the MR556A1-SD captures and controls expanding gases instead of
simply trapping the gas with baffles. To further reduce the sound
signature of the MR556 and eliminate flash, the OSS SRM4 module can be
added to the end of the BPR1425.
Important Features of the MR556A1-SD
The HK MR556A1-SD gives the shooter the same outstanding MR rifle
performance with the added benefit of more ergonomic handling and noise
comfort of the new MRS rail system and OSS advanced sound suppression.