The RT-20 (short for Rucni Top 20) is considered one of the most powerful firearms designed for personal shooting. RT-20 is translated from Croatian as "hand cannon" and 20 stands for the caliber in millimeters.
Developed in Croatia in the mid-1990s, the RT-20 was designed as an anti-materiel and anti-armor long-range rifle. It is currently manufactured by the RH-Alan company. The RT-20 had seen some action in the Balkan conflicts since then, and is officially used by the Croatian army.
The RT-20 is single-shot bolt-action rifle in a bullpup configuration. The overall construction of RT-20 is relatively simple, but features a curious solution to work around the recoil of the 20×110mm Hispano rounds used in it.
The RT-20 utilizes a reactive counter-recoil tube located above the barrel. The tube is opened into a reactive nozzle on the rear end above shooter's shoulder, which is also connected to the barrel on the front end in the middle section of barrel. While shooting, a portion of the resulting gasses pass through the recoil tube and out of reactive nozzle, dampening the recoil.
A massive muzzle brake further dampens the recoil, making it tolerable for shooting. The RT-20 has no iron sights and is outfitted with telescopic sight that is offset to the left.
The RT-20 has a very long effective range of about 1800 meters and a high terminal effectiveness. Among others, the most prominent disadvantage is the backblast, which is similar to that of the RPG-7.