During the MSPO 2018 in Kielce, the Fabryka Broni Łucznik-Radom, Polish main military firearms manufacturer, will unveil the latest prototype version of MSBS-5,56B rifle, a bullpup variant of the MSBS/GROT assault rifle.
The head designer had decided to implement a couple of important modifications which allowed to lighten the weapon. The weight was decreased from 4050 grams to 3600 grams. The pictured prototype had a 16” fluted barrel.
Top: MSBS-5,56B 2018, bottom: legacy MSBS-5,56B.
Following updates were implemented:
Re-designed modular handguard with M-LOK attachment slots is now monolithic part. Its mounting to the upper receiver was changed. The handguard now allows to fix the bayonet to the rifle. In opposite to the standard MSBS-5,56 rifle, the bayonet is fixed not to the bottom of muzzle device, but to the top.
Top Picatinny rail was extended when compared to the legacy bullpup version.
The shape and profile of the lower receiver was changed in the area of grip and trigger guard. The pistol grip was moved forward for about an inch.
The way the upper and lower receivers are connected in the back of the rifle was changed. The big chunk of metal was removed and replaced with a smaller and flatter part. The butt-stock pad is integrated with simple cheekpiece and can be replaced with different one if there is such requirement. The final shape of the stock part was changed, and it has now an open-end with sling loop.
The magazine release mechanism was introduced. The pressure required to activate the release lever is now same on the whole surface of the lever pad. Secondary magazine release lever was added on the left side of the magazine well.
The flared inside of the magazine well was extended.
New trigger. Trigger is now common with the standard MSBS-5,56 assault rifle and only requires replacing two parts before change. Trigger is also working more smoothly now.
Re-designed bolt release mechanism lever on the rear side of the magazine well. It is placed in the hollow and might be easily operated with both right and left hand.
The middle QD sling attachment point (the rifle has three QD mounts on each side) was moved from the magazine well area to the front. Now, there are two QD attachment points on the handguard.
The latest version of MSBS-5,56B bullpup rifle will be shown during MSPO 2018 trade show on C-1 booth.