We got to shoot the new HK556SD in the media day. We were very impressed by the OSS suppressor. With the BPR ( back pressure regulator) and SRM ( signature reduction module), the MR556 SD shot like a .22 rim fire. There was almost no recoil and muzzle flip, in addition to sound suppression.
The most significant feature of the OSS is that the “core” of the suppressor is permanently attached to the barrel. The only registered suppressor is the outer cylinder. In addition, the wear part of the entire suppressor is a 40 dollars detachable gas bleeder at the muzzle, which will last 10,000 rounds and could be changed by simply unscrewing off the muzzle.
Most suppressors are internally arranged as a series of expansion chambers linked up in linear fashion. The OSS works in a reverse manner. Gas is bled off into the expansion chamber between the inner and outer cores at the end, and flow in the opposite direction to the bullet travel. The chamber between the inner and outer cores is partitioned by a series of fins spiraling around the inner core.
For those who cannot own suppressor, OSS also has a flash suppressing compensator, which has a similar geometry as the gas bleeder in the suppressor. During my test fire, I found that it is extremely effective in reducing muzzle flip. I asked the OSS staff if obstruction by mud would create a barrel explosion due to the exposed complex geometry , he reassured me that the muzzle would just blow the debris out without creating an obstruction.
Finally, according to HK staff, the keymod rail will be available for purchase. With the keymod rail installed, he estimated that the weight of the MR556 will be brought down to under 8lb (instead of 8.4lb)
The most significant feature of the OSS is that the “core” of the suppressor is permanently attached to the barrel. The only registered suppressor is the outer cylinder. In addition, the wear part of the entire suppressor is a 40 dollars detachable gas bleeder at the muzzle, which will last 10,000 rounds and could be changed by simply unscrewing off the muzzle.
Most suppressors are internally arranged as a series of expansion chambers linked up in linear fashion. The OSS works in a reverse manner. Gas is bled off into the expansion chamber between the inner and outer cores at the end, and flow in the opposite direction to the bullet travel. The chamber between the inner and outer cores is partitioned by a series of fins spiraling around the inner core.
For those who cannot own suppressor, OSS also has a flash suppressing compensator, which has a similar geometry as the gas bleeder in the suppressor. During my test fire, I found that it is extremely effective in reducing muzzle flip. I asked the OSS staff if obstruction by mud would create a barrel explosion due to the exposed complex geometry , he reassured me that the muzzle would just blow the debris out without creating an obstruction.
Finally, according to HK staff, the keymod rail will be available for purchase. With the keymod rail installed, he estimated that the weight of the MR556 will be brought down to under 8lb (instead of 8.4lb)
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