The CZ 550 Magnum production rifle series has become one of the highest-rated among those who hunt big and dangerous game. The popularity of the 550 Magnum rests largely on its quality, proven reliability, strength and adaptability – all at an affordable price. In Africa, you will find these rifles in the hands of many professional hunters, game rangers, field-guides and sport hunters.
The action safely handles very powerful rimless cart-ridges. Many custom hunting rifles in calibres from .375H&H all the way up to .505 Gibbs are built on CZ 550 Magnum actions. Some hunters bought these rifles in more affordable calibres like the .375H&H and later rebarrelled them for bigger cartridges.
The 550 Magnum is a modified version of Czechoslovakia’s highly successful CZ ‘Brno’ ZKK 602 action for rifles in magnum-length and big-bore sporting cartridges. In the 1971 edition of Bolt Action Rifles, Frank de Haas wrote that the CZ ‘Brno’ ZKK series of rifles included three models: the standard length action ZKK-600 for ‘standard calibres’ such as the .30-06; the ZKK-601 for short cartridges like the .308 Win; and the ZKK-602 for magnum-length cartridges such as the .375H&H. The earlier 601 and 602 actions had pop-up aperture sights built into the receiver bridge; later this sight was discontinued. Apart from action length and bolt-face/extractor dimensions appropriate to calibre, all ZKK actions were alike. The ZKK 602 is celebrated for being as robust and reliable as its ancestor, the Mauser Model 98, regarded by many as the most successful bolt-action ever.
While the CZ 602 and 550 Magnum designs are not precise copies of the Mauser, both employ the Mauser 98’s broad, non-rotating extractor claw. In Africa’s tropical climates, temperatures reach levels that can significantly increase chamber pressures, potentially causing the fired cases of powerful cartridges to bind themselves to the chamber walls, rendering them very difficult to extract. In such hot and dusty conditions, the Mauser 98 extractor design becomes a form of life-assurance. The broad, robust extractor claw grips a very generous section of the case rim, and in conjunction with the massive camming power of the Mauser-type bolt action, affords maximum reliability of extraction and ejection. Conversely, in non-Mauser 98 type designs, the narrow, hinged, hook-type extractor claws recessed into the bolt head have been known to break or rip through the soft brass rim of a case that has stuck in the chamber. This is what makes actions of the Mauser 98 pattern, namely the Pre-64 M70 Winchester, CZ 602 and 550, et al, the preferred choice of Africa’s professionals. The CZ’s Mauser-type extractor claw is its most important feature.
Read the full article in the June2020 issue of Magnum.