The CZ-550 is a bolt-action hunting rifle series manufactured by Česká zbrojovka Uherský Brod (CZ UB). The CZ 550 series is available with a medium or magnum sized action. The CZ 550 rifle is based on the Mauser 98 rifle.
Since the CZ 550 magnum size action can be chambered for super magnum cartridges some elephant gun wildcat cartridges were tested and others specially designed (see .600 Overkill) with and for this action.
Design details
As a modern civilian offspring of the Karabiner 98k service rifle the CZ 550 series offers several features and factory options, that are also typical for sporterised Mauser Karabiner 98k ex-service rifles, ranging from various technical departures from the basic Mauser service rifle on to luxury wood grades. Some of the available options were originally developed and introduced by John Rigby & Co. on Rigby Mauser hunting rifles.
Operating mechanism
The operating mechanism of the CZ 550 series is based on the Mauser M 98 controlled-feed bolt action system. The original Mauser M 98 is a simple, strong, safe, and well-thought-out design that inspired other military and hunting/sporting rifle designs that became available during the 20th century. For the CZ 550 series the action system is machined out of high-grade steel. It also features a double square bridge for mounting a telescopic sight.
Features
The CZ 550 system consists of a receiver that serves as the systems shroud and a bolt group of which the bolt body has three locking lugs, two large main lugs at the bolt head and a third safety lug underneath the bolt handle acting as a backup. The bolt handle is permanently attached to the bolt and is turned-down and backwards for use with optical sights.
Another distinctive feature of the CZ 550 system is the controlled-feed mechanism, consisting of a large, non-rotating claw extractor that engages the cartridge case rim as soon as the round leaves the magazine and firmly holds the cartridge case until the round is ejected by the ejector, mounted inside the receiver. The CZ 550 bolt action will cycle correctly irrespective of the way the rifle is moved or positioned during the bolt cycling action or if the cartridge has been fired or not. Only if the bolt is not brought back far enough, sharply enough, in a controlled round feed bolt action the cartridge case may not be cleanly ejected and a jam may result.
The bolt houses the firing pin mechanism that visually and tactilely protrudes from the rear of the bolt indicating if the action is cocked or not. A small disassembly button offers the possibility to access the firing pin and spring.
The action features a large gas relief hole at the bolt body designed to protect the user's head in case of a primer or cartridge rupture or detonation. When the action suffers a catastrophic failure it is designed to deflect the debris away from the operator's face.
The CZ 550 bolt group can be easily removed from the receiver simply by pushing the disassembly button, located at the left wall of the receiver, and then by rotating and pulling the bolt out.
Safety
A horizontal two-position safety is mounted on the right side just behind the bolt system. The safety locks the bolt and sear. The user interface consists of a rather compact grooved button that should ensure good operability of the safety with low mounted aiming optics.
Trigger
The single set trigger on a CZ-550 operates as a single stage during normal operation. However, when it is desirable to have less trigger pull, such as for longer range or very accurate shooting, the trigger can be pushed forward, making it a set trigger. These rifles are factory set with the trigger pull set at approximately in standard mode and approximately in the set mode. Both settings are adjustable.
Barrel
The rifles have hammer forged steel barrels. The twist rate is caliber specific.
Ammunition feeding
For some models the internal magazine of the CZ 550 series M 98 system consists of an integral box machined to match the cartridge for which the rifle was being chambered, with a detachable floorplate, that can hold up to 5 standard sized rifle cartridges. Other models are fed by detachable box magazines, that can hold up to four standard-sized rifle cartridges. The detachable magazines are released by a magazine release located at the front of the trigger guard.