by PAUL FITCH

If there’s any weapon that deserves the most credit for beating back Nazi Germany, it might be the legendary bolt-action Mosin-Nagant rifle.

The Soviet Union made them in absolutely huge numbers — and they’re still available and rather cheap compared to their contemporaries. What’s more extraordinary is that the basic design is more than a century old.

Even now, rebels carry Mosin-Nagants alongside more modern weapons as in conflicts from Ukraine to the Middle East.

But there’s good reasons for that. It’s because of the rifle’s simplicity, ruggedness and a design philosophy summed up as “if it ain’t broke, don’t fix it.”

During the late 19th century, the Russian Empire wanted to upgrade its arsenal. Instead of its existing Berdan II single-shot rifles, the empire wanted a cutting edge repeating weapon that fired smaller but higher-pressure metallic cartridges.

Russian army officer and engineer Sergei Ivanovich Mosin designed the new rifle’s action — a straightforward bolt action that “cocks-on-open.” Belgian weapons designer Leon Nagant improved the weapon’s feeding mechanism.

In 1891, Russia adopted Mosin’s rifle and christened it the “Three-Line Rifle, Model of 1891.”

The rifle has few moving parts — which is part of its beauty. Its beefy mechanism only consists of seven pieces, while its trigger group consists of three. The heavy stock is Russian birch wood.

These rifles have seen a lot of battles. Russians troops carried them during the 1905 war with Japan. The rifles served with Russian troops during World War I. The Bolsheviks carried those same rifles again when they fought to create the Soviet Union from 1917 to 1922.

But the Soviets introduced the most popular variant — the Mosin-Nagant 91/30. In 1930, the Soviets modernized the rifle, installed several major upgrades and added the “30” designation to its name.

Its basic design was almost 40 years old then, and people are still using it.

Gunsmiths shortened the 91/30 by a few inches, and calibrated its sights in meters. The older imperial rifles have sights calibrated in archaic arshin units standardized during the reign of Peter the Great.

But if you see a Mosin-Nagant, it’s most likely a 91/30 from World War II with sights measured in meters. The Soviet army entered the war equipped with this triokhlineika — or “three-liner” — as their standard issue bolt-action battle rifle.