MSBS Grot: The Complete History of Poland’s New Army Rifle

The MSBS Grot is Poland’s current military service rifle, and has gone through several iterations in the many years of its development that led to its current 2nd generation form. It is best known in the US as a rifle designed to be interchangeable between standard and bullpup layout, although that capability was dropped when the Polish Army opted not to adopt it. Fundamentally, the Grot (“Arrow” or “Spear”) is a short-stroke gas operated, rotating bolt, 5.56mm system derived from the AR-18 system. It spent several years tied up in bureaucratic limbo as part of Project Tytan – Poland’s version of a Future Soldier program. It was finally dragged into mainstream adoption when the newly formed Polish Territorial Defense Force adopted it.

Today we will be tracing the development of the Grot form its very first mockups through the preproduction prototypes, the first generation rifle, and the now-standardized second generation – plus a look as the grenade launchers developed alongside it. I would like to give a very big thanks to Fabryka Broni in Radom, Poland for the full access they gave me to this rifle. While the teething issues the Grot had in development are typical of new rifle designs, not many companies are willing to share the whole project history, warts and all. I really appreciate that FB did!


  1. There is already a bullpup version KIT, ready to sell on the civil market. It will be available in Poland in 2023. The Polish army ends trials of this configuration and thinking about adopting it as MSBS version for tank crews, drivers, etc. Also, worth mentioning that GROT rifles can be spotted in Ukraine right now. More about that KIT on this video: Moreover GROT is fully modular, barrels, calibers, all can be changed. For example, here you can see GROT 7.62N in sharpshooter configuration:

  2. I don’t know if anyone has noticed, but the name sounds like it came from Marvel’s Masters of the Universe. I am Grot!

  3. If you want to have a short stroke gas piston, why not start with a Dragunov. The AR-18 bolt have zero primary extraction, which make the Garand (Kalashikov is a Garand)bolt better. The Garand do have primary extraction. I will not say the Grot is model after an AR-18, but modeled after a HK G-36, excluding the G-36 gas regulator. The AR-18 have twin recoiled springs. The Sig M5 spear and FN Scar is model after the Ultimax, not the AR-18. The AR-18 my be the father of the G-36 and Ultimax, but I think the G-36 and Ultimax is more of direct parentage to the Grot, M5 and Scar.

Leave a Reply

Your email address will not be published.