MSBS Grot
Fabryka Broni Lucznik - Radom · Assault Rifle · In Production · 2016
Also known as: MSBS Radon, Grot C16, FB MSBS Grot, Modulowy System Broni Strzeleckiej
Overview
The MSBS Grot (Modulowy System Broni Strzeleckiej - Modular Small Arms System) is a Polish assault rifle developed by the Military University of Technology (WAT) in Warsaw in cooperation with Fabryka Broni Radom. Adopted by the Polish Armed Forces in 2016 as a replacement for the FB Beryl, the Grot is a modular weapons platform built around a short-stroke gas piston system with a rotating bolt. Its defining feature is the ability to be converted between conventional and bullpup configurations by repositioning the fire control group relative to the magazine well, though only the conventional layout has been adopted for military service. The rifle features full ambidextrous controls, a side-folding adjustable stock, free-floating barrel, and accepts standard STANAG magazines. The platform supports multiple barrel lengths and calibers, with the standard C16 variant using a 406mm barrel. By 2021, the Polish Territorial Defence Force had received approximately 60,000 Grot rifles, with additional orders for the regular Polish military.
Specifications
| Weight (empty) | 3650 g (128.8 oz) |
| Weight (loaded) | 4250 g (149.9 oz) |
| Overall Length | 900 mm (35.43") |
| Folded Length | 670 mm (26.38") |
| Barrel Length | 406 mm (15.98") |
| Height | 237 mm (9.33") |
| Width | 86 mm (3.39") |
| Action Type | Gas Operated Short Stroke |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Single Stage |
| Magazine Capacity | 30 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 890 m/s (2920 fps) |
| Muzzle Energy | 1600 J (1180 ft·lbf) |
| Effective Range | 500 m (547 yd) |
| Rate of Fire | 700 rpm |
| Barrel Rifling | Right Hand |
| Rifling Twist | 178 mm (7.01") |
| Number of Grooves | 6 |
| Frame Material | Aluminum Alloy |
| Barrel Material | Steel |
| Stock Material | Polymer |
| Finish | Phosphate |
Calibers
- 5.56x45mm NATO · primary · 5.56x45mm NATO — also known as 5.56mm NATO, 5.56x45mm, .223 Remington
Features
- Firing modes: Semi Automatic, Full Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Ambidextrous Safety Selector, Firing Pin Block
- Features: Folding Stock, Adjustable Stock, Select Fire, Free Floating Barrel, Picatinny Rail, Rotating Bolt, Short Stroke Gas Piston, Ambidextrous Controls, Modular Design, Bayonet Lug, Grenade Launcher Compatible, Stanag Compatible Magazines, Quick Change Barrel
Variants
- MSBS Grot A0 (C16 FB-M1) — Initial Production
- MSBS Grot A2 — Improved
- MSBS Grot A3 — Latest
- MSBS Grot B (Bullpup) — Bullpup
- MSBS Grot 762N — Designated Marksman
- MSBS Grot S16 — Civilian
Service history
Operators
- Polish Armed Forces · adopted 2016
- Polish Territorial Defence Force · adopted 2017 · as MSBS Grot C16 FB-M1
- Ukrainian Armed Forces · adopted 2022
- Rwanda Defence Force
Conflicts
- Russo-Ukrainian War (2022-present)
Production
Estimated total produced: 70,000 · Production years: 2016-present
Over 60,000 delivered to Polish Territorial Defence Force by 2021. Polish MoD ordered 53,000 total. Additional rifles donated to Ukraine and exported to Rwanda.
Origin
Country of origin: Poland
Designer: Military University of Technology (WAT) / FB Radom
Notes
The MSBS program began in 2007 with the goal of creating a truly modular weapon system that could adapt to different combat roles. While the bullpup variant (Grot B) was developed and tested, only the conventional layout was adopted due to practical considerations. The Grot A2 improved version addresses several issues identified in the initial A0/C16 FB-M1 production model, including improved trigger feel and enhanced reliability. The A3 variant was revealed in 2024 featuring further weight reduction to 3.4 kg and ergonomic improvements. Poland donated approximately 10,000 Grot rifles to Ukraine in 2022 following the Russian invasion. A 7.62x51mm NATO designated marksman variant (Grot 762N) and a 7.62x39mm export variant are also available.
Background
The MSBS Grot represents Poland's first entirely indigenous assault rifle design since World War II, breaking decades of dependence on Soviet-derived weapons like the AK and Beryl. The name 'Grot' (Polish for 'arrowhead' or 'spearpoint') was chosen through a public naming competition. The rifle's modular convertibility between conventional and bullpup layouts, while ultimately only adopted in conventional form, demonstrated an ambitious engineering vision that attracted international attention. The donation of Grot rifles to Ukraine in 2022 marked their first use in a major armed conflict.