On 15 December the Fabryka Broni Łucznik-Radom board confirmed that semi-automatic variant of the MSBS-5,56K/Grot C16 (MSBS-5,56 new name, 2017-09-05) in classic configuration (non-bullpup) chambered in 5,56×45 mm/.223 Remington, will be avalible on the civilian market in the first quarter of 2018.

First pieces of semi-auto MSBS-5,56K rifles were developed near the end of 2014 and shown at 2015 SHOT Show. / Photo: Remigiusz Wilk

First pieces of semi-auto MSBS-5,56K rifles were developed near the end of 2014 and shown at 2015 SHOT Show. / Photo: Remigiusz Wilk

As MILMAG found out, Radom Factory already completed several prototype rifles set up with semi-auto trigger mechanisms. The internal trials are planned to start in January 2018. The semi-auto Grot S will closely resemble it’s military variant. The ability to easily change the barrel will be carried over from the select-fire version, which means that in the future we may expect the other barrels avalible for sale (shorter, longer or heavy-profile).

Outside differences from the military version (MSPO17: Grot for WOT, 2017-09-10), (MSBS-5,56 rifle for WOT and WS, 2017-06-07) other than markings, are lack of full-auto position on the fire-selector and slightly altered muzzle device, which doesn’t allow for the use of bayonet. Grot S will have a diffrent lower reciever that will not accept the select-fire trigger mechanism.

To comply with the European and American laws, the bolt carrier won’t be compatible with the military variant as is with the Radom Sport rifles (civilian version of wz. 96 Beryl rifles). That’s also the reason behind the altered muzzle device mentioned earlier. The bolt carrier will also lack some of the tungsten weights used in military variant to prevent the bolt from bumping out of battery during full-auto fire. This change will also reduce the felt recoil of the Grot S.

Another difference is the changed barrel rifling in the semi-auto MSBS-5,56K. The military barrels have 1:7 rifling to stabilize the 62-grain projectiles of the M193/M855 5,56×45 mm NATO rounds. Grot S will have the 1:9 twist rate (as in Radom Sport rifles) to help with lighter 55-grain projectiles often found in civilian .223 Remington rounds. The 16-inch barrel will end with a non-pinned birdcage-type flash hider sitting on 1/2×28 threads, to allow for use of any commercial muzzle device compatible with that thread.