[4] The MSBS program was in development since 2007 by the Military University of Technology (WAT) in Warsaw with cooperation from the firearms manufacturer Fabryka Broni Radom,[5][6] and was designed to replace the FB Beryl as the standard-issue service rifle of the Polish Armed Forces.

[7] Additional tests have also shown that MSBS is less susceptible to jamming when using lower quality ammunition or when it is insufficiently maintained,[8] and had a more manageable recoil when fired in full-auto compared to other assault rifles chambered in the 5.56 cartridge, such as FB Beryl, HK416, FN SCAR-L or CZ BREN 2.

If necessary, a soldier can sacrifice, for example, one standard assault rifle to quickly repair a light machine gun during a firefight.

MSBS may also be used with components other than the ones manufactured domestically, and it is the first Polish rifle fully compliant with the NATO standards.

The MSBS-5.56 features fully ambidextrous controls and Picatinny rail, and it may also be fed from standard STANAG magazines.

[1][13][14] On May 9, 2022, the public was informed about the conclusion of an agreement between the Polish Armaments Group and an undefined East African country for the supply of an unspecified number of MSBS Grot assault rifles chambered for 7.62×39mm rounds as specified by the customer, along with 40 mm grenade launchers and optical sights DCM-1 Szafir [15] manufactured by PCO S.A.[16] In January 2025, a photo appeared on the X website (formerly Twitter) showing small arms captured by soldiers of the Democratic Republic of the Congo from M23 rebels - among them a Beryl carbine powered by 7.62 x 39 mm ammunition.

The changes included a longer upper receiver with M-LOK compatible handguard and heat stop covers, a quick-detach sling mounting points, FB made pistol grip instead of previous Magpul pistol grip due to shortage during mass production, reinforced buttstock, reinforced secondary sights, strengthened, thicker charging handle, reinforced firing pin (not interchangeable with the old one from M1), FB made polymer translucent magazine, new lock (not interchangeable with the old one from M1), and new slide (not interchangeable with the old one from M1).

It was led by the team of Fabryka Broni Łucznik-Radom and Wojskowa Akademia Techniczna (WAT) engineers.

[30][31] The Grot 7.62N is designed as a semi-automatic rifle but project engineers declared that a fully automatic configuration can be developed if required.