The MSBS Grot (, ) is a family of modular rifles developed and manufactured by
FB Radom. Early prototypes were known as the ''MSBS Radon''.
There are two variants of the MSBS Grot:
assault rifle
An assault rifle is a select fire rifle that uses an intermediate cartridge, intermediate-rifle cartridge and a Magazine (firearms), detachable magazine.C. Taylor, ''The Fighting Rifle: A Complete Study of the Rifle in Combat'', F.A. Moyer '' ...
(in conventional and bullpup configurations) and
designated marksman rifle. Both variants use the same lock and the modular structure ensures the interchangeability of parts and accessories. The MSBS is intended to ultimately replace the
FB Beryl as the Polish
service rifle.
History
The MSBS program was in development since 2007 by the
Military University of Technology (WAT) in
Warsaw
Warsaw, officially the Capital City of Warsaw, is the capital and List of cities and towns in Poland, largest city of Poland. The metropolis stands on the Vistula, River Vistula in east-central Poland. Its population is officially estimated at ...
with cooperation from the firearms manufacturer
Fabryka Broni Radom, and was designed to replace the
FB Beryl as the standard-issue service rifle of the Polish Armed Forces.
During initial tests conducted by the Military University of Technology, the MSBS-5.56 and its counterpart
HK416 were subjected to comparative testing of the barrel and hand-guard for overheating during an intensive firing schedule. According to the tests, MSBS yielded the better results of the two rifles despite having a relatively light and longer barrel profile. Additional tests have also shown that MSBS is less susceptible to jamming when using lower quality ammunition or when it is insufficiently maintained, 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.
One of the main design characteristics of the MSBS-5.56 is the modular weapon system. If necessary, a soldier can sacrifice, for example, one standard
assault rifle
An assault rifle is a select fire rifle that uses an intermediate cartridge, intermediate-rifle cartridge and a Magazine (firearms), detachable magazine.C. Taylor, ''The Fighting Rifle: A Complete Study of the Rifle in Combat'', F.A. Moyer '' ...
to quickly repair a
light machine gun
A light machine gun (LMG) is a light-weight machine gun designed to be operated by a single infantryman, with or without an assistant, as an infantry support weapon. LMGs firing cartridge (firearms), cartridges of the same caliber as the othe ...
during a firefight. Another feature of the MSBS Grot is barrel changeability, as found on the
Steyr AUG. This means a soldier may be able to adapt their rifle based on the environment they are in, such as converting a
carbine to a designated
marksman rifle, in order to engage targets at a greater range. The benefits of this feature allow an
infantry
Infantry, or infantryman are a type of soldier who specialize in ground combat, typically fighting dismounted. Historically the term was used to describe foot soldiers, i.e. those who march and fight on foot. In modern usage, the term broadl ...
squad
In military terminology, a squad is among the smallest of Military organization, military organizations and is led by a non-commissioned officer. NATO and United States, U.S. doctrine define a squad as an organization "larger than a fireteam, ...
to have fewer specialised weapons. 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
The 1913 rail (MIL-STD-1913 rail) is an American rail integration system designed by Richard Swan that provides a mounting platform for firearm accessories. It forms part of the NATO standard STANAG 2324 rail. It was originally used for mount ...
, and it may also be fed from standard
STANAG magazines.
Currently, the rifle is in service with the Polish
Territorial Defence Forces and is scheduled to replace
FB Beryl as the primary
infantry
Infantry, or infantryman are a type of soldier who specialize in ground combat, typically fighting dismounted. Historically the term was used to describe foot soldiers, i.e. those who march and fight on foot. In modern usage, the term broadl ...
weapon and
service rifle of the
Polish Armed Forces
The Armed Forces of the Republic of Poland (, ; abbreviated SZ RP), also called the Polish Armed Forces and popularly called in Poland (, roughly "the Polish Military"—abbreviated ''WP''), are the national Military, armed forces of the Poland, ...
.
Following the adoption of the MSBS-5.56 by the Polish military, the ''Grot'' moniker has been added to the MSBS name in honor of the
Home Army
The Home Army (, ; abbreviated AK) was the dominant resistance movement in German-occupied Poland during World War II. The Home Army was formed in February 1942 from the earlier Związek Walki Zbrojnej (Armed Resistance) established in the ...
commander, General
Stefan "Grot" Rowecki.
During the
2022 Russian invasion of Ukraine
On 24 February 2022, , starting the largest and deadliest war in Europe since World War II, in a major escalation of the Russo-Ukrainian War, conflict between the two countries which began in 2014. The fighting has caused hundreds of thou ...
10,000 Grot C16A2 rifles were sent to the
Ukrainian military.
On May 9, 2022, the public was informed about the conclusion of an agreement between the Polish Armaments Group and an undefined
East Africa
East Africa, also known as Eastern Africa or the East of Africa, is a region at the eastern edge of the Africa, African continent, distinguished by its unique geographical, historical, and cultural landscape. Defined in varying scopes, the regi ...
n 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 manufactured by PCO S.A.
The Grot A3 was publicly presented at the Grotowisko 2024 small-arms conference, held in
Zegrze from June 22 to 23, 2024.
Its development was based on lessons learned from the conflict in Ukraine.
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
The Democratic Republic of the Congo (DRC), also known as the DR Congo, Congo-Kinshasa, or simply the Congo (the last ambiguously also referring to the neighbouring Republic of the Congo), is a country in Central Africa. By land area, it is t ...
from
M23 rebels - among them a Grot carbine powered by 7.62 x 39 mm ammunition.
Variants

The following variants were designed based on the requests from the Polish Armed Forces to replace currently used firearms such as the
AKM,
FB Beryl,
FB Mini-Beryl
The FB Mini-Beryl is a Polish compact assault rifle (carbine) derived from the FB Beryl service rifle and chambered for 5.56×45mm. It was developed in parallel with the wz. 96 Beryl by the FB "Łucznik" Radom, Fabryka Broni in Radom and int ...
, and
Pallad grenade launcher.
The MSBS GROT is a selective fire modular assault rifle which is capable of semi-automatic, 3-round burst and fully automatic fire. It has a cyclic rate of fire of around 700–900 rounds per minute.
Currently only the MSBS Grot C in assault rifle, carbine, configuration with a grenade launcher, MSBS Grot R and MSBS Grot S are available. The MSBS Grot B, and the machine gun and designated marksman rifle configurations are not yet produced. Conversion kits between variants are also not yet available. Conversion kit to change the calibre to
7.62×39mm is available.
* MSBS Grot C (, ) is the classic configuration of the MSBS-5.56, chambered in either
5.56×45mm NATO or
7.62×39mm cartridge with a folding and retractable stock.
** MSBS-5,56A0 - initial production, 1,000 produced.
** FB-M1 (MSBS-5,56A1) - first production batch: modified charging handle and additional strap mount point on the
picatinny rail
The 1913 rail (MIL-STD-1913 rail) is an American rail integration system designed by Richard Swan that provides a mounting platform for firearm accessories. It forms part of the NATO standard STANAG 2324 rail. It was originally used for mount ...
.
** FB-M2 (MSBS-5,56A2) - second production batch: longer
handguard to cover the gas block, reinforced
firing pin for dry fire practice, improved
pistol grip
On a firearm or other tools, a pistol grip is a distinctly protruded handle underneath the main mechanism, to be held by the user's hand at a more vertical (and thus more ergonomic) angle, similar to how one would hold a conventional pistol.
...
and
buttstock.
* MSBS Grot B (, ) – is similar to the MSBS Grot C but in bullpup configuration. The MSBS Grot was designed to share a universal upper receiver for both the classic and bullpup configurations, which leads to the ease of conversion by simply swapping the lower receiver.
* MSBS Grot R – is the representative variant of the MSBS Grot designed to be used by
honor guards which has been adapted to fire blanks and withstand drills. With the modularity of the MSBS Grot, the barrel can be swapped to fire live ammunition.
* MSBS Grot S – civilian semi-automatic only variant of the MSBS Grot without the bayonet-mount, available with 4 different variants of barrels: 10.5-, 14.5-, and 16-inch in
.223 Remington and 16-inch in
7.62×39mm.
Both the MSBS Grot C and MSBS Grot B are planned in 5 different configurations and have many common interchangeable parts and can be converted from one to the other:
*Assault rifle – a standard assault rifle configuration with barrel.
*Assault rifle with
underbarrel grenade launcher – similar to the assault rifle configuration but with a
40×46mm underbarrel grenade launcher equipped.
*Carbine – a short barrel variant with a barrel.
*Carbine with underbarrel grenade launcher – similar to the carbine configuration but with a 40×46mm underbarrel grenade launcher equipped.
*Machine gun – essentially an automatic rifle variant for both Grot C and Grot B. It features a heavier barrel fitted with a flash hider, and the bayonet-mount was removed. This variant is meant to be used with high-capacity magazines. Surefire MAG5-60 were used for demonstration purposes.
*Designated marksman rifle – a designated marksman rifle variant fitted with a lighter and more precise 16 in (410 mm) and 20 in (508 mm) barrel, and has a two stage trigger group.
;Polish military adoption
Since the
Polish ministry of defence ordered 53,000 of the MSBS assault rifles, Fabryka Broni has introduced a military naming designation for the MSBS series.
Grot – After the official adoption of the MSBS-5.56 by the Polish Armed Forces, the Grot name was added.
C, B, R, S – ''variants'': classic, bullpup, representative, sport (semi-auto civilian). Denoted after the Grot designation.
10, 16, 20 – ''barrel lengths'', in inches. So far only the 16 in (406 mm) has been adopted by the Polish military.
C, G, M, PS – ''configurations'': carbine, variants with grenade launcher, automatic rifle, designated marksman rifle. Denoted after the barrel length designation.
FB – Fabryka Broni, the manufacturer of this weapon system.
M(x) – number of series (x stands for the generation, for examples, ''M1'' means first generation, ''M2'' is second generation, ''M3'' is planned third generation).
The ''M2'' was developed to address the issues found on the early production models. The bullpup configuration did not receive the M2 upgrade due to the lack of interest from the Polish military. 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).
Grot 762N
Grot 762N is a
semi-automatic designated marksman rifle chambered in
7.62×51mm NATO cartridge.
The MSBS-7.62N project began in the end of 2015 when Polish Military of Defence announced analytical works for the replacement program of their
SVD Dragunov marksman rifle and supplement the
bolt-action
Bolt action is a type of manual Action (firearms), firearm action that is operated by ''directly'' manipulating the bolt (firearms), turn-bolt via a cocking handle, bolt handle, most commonly placed on the right-hand side of the firearm (a ...
TRG-22 and
Tor sniper rifles currently in service. It was led by the team of Fabryka Broni Łucznik-Radom and Wojskowa Akademia Techniczna (WAT) engineers.
The Grot 7.62N has two different configurations; one with a 508 mm (20 in) barrel with a fixed adjustable stock and the other with 406 mm (16 in) barrel with the MSBS Grot C's adjustable side-folding stock. Both configurations are part of the MSBS family and some of the parts of the Grot 762N, such as the stock, handguard, pistol grip, and trigger are interchangeable between 5.56mm and 7.62mm models.
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.
Users
* :
Polish Armed Forces
The Armed Forces of the Republic of Poland (, ; abbreviated SZ RP), also called the Polish Armed Forces and popularly called in Poland (, roughly "the Polish Military"—abbreviated ''WP''), are the national Military, armed forces of the Poland, ...
, 184,000 planned by 2026.
**
Territorial Defence Force, 53,000 in 2017.
* : On September 1, 2023, PGZ concluded a contract for the supply of MSBS Grot rifles with an unspecified East-Central African country. On January 31, 2024, the Defense24 portal listed Rwanda as the recipient of Polish rifles, but it is not certain whether the deliveries concern Grot or other rifles. In 2024, photos circulated on the web showing a Rwandan soldier with a 7.62x39 Grot fitted with a GP grenade launcher.
* : 10,000 Grot C16 FB-M1 and A2 variant assault rifles donated to the
Ukrainian Armed Forces during the
2022 Russian invasion of Ukraine
On 24 February 2022, , starting the largest and deadliest war in Europe since World War II, in a major escalation of the Russo-Ukrainian War, conflict between the two countries which began in 2014. The fighting has caused hundreds of thou ...
.
In 2023, it was announced that an unspecified number of Grot C16 A2 rifles had been ordered by Ukraine, but later on such claims have been denied.
* : Unknown quantity sold to Special Operations Command (USSOCOM).
Non-state users
*
March 23 Movement
*
Ingush Liberation Army[https://x.com/war_noir/status/1935001174194749445]
See also
*
FB Beryl
*
FN SCAR
*
Remington ACR
References
Other sources
*
Pierwszy pokaz MSBS-5,56' in:
Altair, 12 December 2009
*
Nowa polska broń – MSBS-5,56' in:
Altair, 15 December 2009
*
MSBS-5,56 już strzela' in:
Altair, 16 December 2009
*
Rodzina MSBS-5.56 W Czerwcu' in:
Altair, 22 March 2010
*
Nowy MSBS-5,56' in:
Altair, 9 August 2010
*
MSBS-5,56 w nowej szacie' in:
Altair, 5 October 2010
*
Giwera przyszłości' in:
Polska zbrojna, 30 December 2008
*
MSBS-5,56 w Pułtusku' in:
Altair, 4 June 2011
*
MSBS do amunicji 7,62mm x 39' in:
Altair, 21 September 2014
*
Prototypy karabinów MSBS-7,62 na MSPO' in
Altair, 9 January 2016
*
Complete family of MSBS-5,56 rifles' 5, June 2018
External links
Fabryka Broni "Łucznik" Radom home page
{{DEFAULTSORT:Msbs Radon
5.56×45mm NATO assault rifles
7.62×39mm assault rifles
Designated marksman rifles
Assault rifles of Poland
Military equipment introduced in the 2010s
Weapons and ammunition introduced in 2018