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Helenius RK-97 APH

1996 MODERN

Helenius RK-97 APH History

The Helenius RK-97 APH is a heavy anti-materiel rifle made in Finland. Available in two different forms, the system uses either 12.7x99mm NATO or Soviet 12.7x107mm cartridges as required, and is a single-shot breech-loading weapon.

The use of these two popular large-caliber projectiles has sparked interest in such systems on the world market. Visually, both versions of the weapon look similar, and both use a "bullpup" style configuration - that is, the magazine feed and action are unconventionally located behind the trigger group.

Stock is made of light metal with padded stock plate and synthetic cheeks. The barrel is 44 inches long and made of heavy duty steel - it was specifically designed to eliminate the effects of the enormous recoil that occurs when firing such a large caliber cartridge. The muzzle brake is removable and has a "Pepperdot" pattern.

The bipod supports the front of the weapon and is not adjustable, but can be folded to varying degrees, making it essentially "indirect" adjustable. Surprisingly, this heavy, large-caliber weapon has been successfully tested with a noise suppression device - a silencer that is simply screwed onto the barrel in place of the muzzle brake. In the absence of iron sights, optical sights are required for effective operation. The optics are mounted on a ring mount on the left or right side of the receiver and can be manufactured differently depending on the operator's preference.

However, sight attachments are available if the operator needs to use an alternate sight.

The operator activates the weapon by depressing the foregrip, then lowers the breech block (RK-97 is classified as a "breech-loaded" weapon system). The breech block itself is unique in that it is a "vertical drop" breech block system. A new cartridge is manually inserted into the breech, then the operator returns the foregrip to its original position and locks the breech block in place.

The weapon is now ready to fire. Essentially, the RK97 uses an action similar to the "pump action" method of a traditional shotgun.

The RK-20 APH is a larger version based on the RK-97 and is used to fire the Russian WWII-era 20x99mm ShVAK cartridge (the Finns refer to this cartridge as 20x100mm - Swak). The RK-20 has a shorter (33.9") but larger overall barrel assembly with a properly sized muzzle brake and improved internal action for a larger cartridge.

The RK-99 APH was introduced in 2000 as an updated form of the original RK-97, using a detachable magazine feeder for repeated firing via an internal rotating bolt mechanism. The barrel is 32.4 inches long, and its internal characteristics are of course different from the base single-shot RK-97. The RK-99 is equipped with a 5-round or 10-round detachable magazine.

While the 10-round firing capability increases the RK-99's endurance on the battlefield, the extra magazine height partially offsets the RK-99's bullpup configuration.

The RK-99MK1 is another single-shot form of the rifle with a different firing action, improving reliability and facilitating the simplified use of different types of ammunition. The RK-99MK2 is loaded with a 20mm ShVAK cartridge and has a shorter barrel length of 31.5 inches.