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Few would argue that the Mauser action is anything less than a classic. The CZ 527 American Synthetic Suppressor Ready (527 SR) utilizes the classic Mauser action while offering modern flair in terms of caliber options and suppressor adaptability. The CZ 527 action is a true micro-Mauser, not a standard Mauser action that has been chopped and re-welded. This makes for a svelte-handling rifle. 

The CZ 527 American SR features an American-style synthetic stock, sporter profile hammer-forged barrel, single set trigger (SST) and a threaded muzzle. CZ has further upped the ante with interesting chambering options in 300 AAC Blackout (300 BLK), which will be evaluated herein (it also comes in 7.62×39). Both cartridges are natural candidates for use in conjunction with the micro-Mauser bolt-action. However, the 300 BLK is a natural match to a rifle intended to accommodate a suppressor.

Credit must be given to CZ for coming up with this for the American market; there are few major firearms companies offering either round in a bolt-action rifle format, let alone with a 5/8×24 threaded barrel ready to accommodate mounting a suppressor.

What role is the CZ 527 SR intended to satisfy? As with most things related to firearms, the answer depends on
the individual situation. Factors such as mindset, personal preference, skill level, training, the need to fulfill  multiple roles and even legal requirements all come into play regarding rifle selection for defense. The CZ 527 SR, with its Mauser action, is definitely at home in a hunting role. The CZ decision to offer a suppressor-ready bolt-action .300 BLK opens up multiple roles. The CZ 527 Suppressor Ready and 300 BLK were made for each other.

The CZ 527 SR has a threaded barrel to accommodate easy adaption to suppressor use.


CZ-USA is based in Kansas City and is a subsidiary of Ceská Zbrojovka Uhersky Brod (CZUB) out of the Czech Republic. CZ’s company history dates back to the mid-1930s. In 1991, it decentralized from government, and in 1992, it privatized to become one of the first East European corporations to emerge from the post-Soviet era to compete in the West.

“The CZ 527 American Synthetic Suppressor Ready (527 SR) utilizes the classic Mauser action while offering modern flair in terms of caliber options and suppressor adaptability.”

In 1997, it came full force into the U.S. market and formed CZ-USA. CZ is one of the world’s largest firearms manufacturers, employing more than 2,000 people and selling its wares in more than 60 countries. CZ products include handguns, shotguns, sporting rifles and military weapons. The CZ 527 SR has a classic sporter  appearance, taking full advantage of the CZ micro-Mauser action to create a great-handling, lightweight rifle. Truly a shortened profile, the CZ 527’s Mauser action is only 6 inches long and saves at least 1 pound over a standard Mauser bolt-action. Positive functioning was never an issue. CZ has fitted the 527 SR with a free-floated, 16.5-inch, hammer-forged barrel with threaded muzzle. CZ barrels are of excellent quality, as is evident by test group consistency and ease of cleaning. Sling swivels are standard features with the CZ 527.

SIG Sauer’s SR762-QD suppressor and proprietary SIG Sauer Taper-Lok muzzle attachment

The CZ 527 SR rifle is fed from a detachable, five-round magazine. This particular 300 BLK rifle might surprise some readers, because the 300 BLK is associated more with AR platforms. A better mixture of a classic bolt with an American utilitarian cartridge would be hard to come by. Anecdotal information compares standard-velocity 300 BLK 115- to 125-grain ammunition as exceeding the ballistics of the 7.62×39 and eclipsing 5.56 NATO in both ballistics and terminal punch. At 300 meters, the 300 BLK has approximately 17 percent more energy than the 7.62×39. The 300 BLK from a 9-inch barrel has the same energy at the muzzle as the M4 with a 14.5-inch barrel chambered in 5.56 NATO and surpasses it as ranges extend.

SIG Sauer’s Taper-Lok muzzle adapter mounted on a CZ 527 SR threaded muzzle

Not surprising, considering that AAC is in the suppressor business, is the ability to choose 300 BLK subsonic loads for optimal use with a sound suppressor. The ability to access either supersonic or subsonic factory ammunition offers great flexibility to the 300 BLK user. Whatever roles the CZ 527 Suppressor Ready is considered for—hunting, personal defense or sport—it fits the bill.

“One crucial improvement with the CZ Mauser is its square bridge design, which allows for an integral scope base. The CZ rings mate up right to the action for solid attachment and help ensure reliable scope zeroes.”


Ammunition tested with the CZ-USA CZ 527 Suppressor Ready was Hornady supersonic 125-grain HP, SIG Sauer Elite 125-grain and 220-grain Match subsonic, and Black Hills Ammunition 125- and 220-grain OTM. What distinguishes the 300 BLK is its ability to access standard supersonic rounds for typical hunting or long-range engagements superior to 5.56mm while maintaining the trump card of subsonic ammunition for when quiet is needed.

CZ’s decision to manufacture a “square bridge” Mauser with integral scope bases will aid in its acceptance by connoisseurs of bolt-action rifles for whom a scope is standard equipment.

A SIG Sauer Tango6 1-6x24mm optic was mounted via CZ 30mm rings. One crucial improvement with the CZ Mauser is its square bridge design, which allows for an integral scope base. The CZ rings mate up right to the action for solid attachment and help ensure reliable scope zeroes. The Tango6 offers a 1x illuminated reticle setting for quick target acquisition at close range with both eyes open. A quick turn of the knob to 6x enables longer precision shots. The SIG Sauer Tango6 is loaded with high-end features: an adjustable, illuminated MOA reticle; extra-low-dispersion glass combined with high-transmittance glass for outstanding light transmission and clarity; and resettable lockable and zero stop turrets. SIG Sauer offers various power ranges and options in the Tango6 model lineup, such as different reticle styles, MRAD or MOA turret adjustments, first or second focal
plane, and so on.

Numerous 300 BLK ammunition loads were used with the
CZ 527 SR, including standard and subsonic loads.


Common to most Mauser designs is the external extractor, which is non-rotating and acts in conjunction with the bolt stop-positioned ejector spur to eject used cases positively. The CZ Mauser bolt retains the bolt head and extractor with the single slotted internal collar of Peter Paul Mauser’s original design.

The legendary performance and loyal following of the Mauser action starts with controlled round feeding. The cartridge is captured and held in place by the claw extractor as it comes free from the magazine and is placed into the chamber. However, CZ has added some improvements: a streamlined bolt sleeve, single set trigger (SST), two-position safety, a stiffer tang and a Winchester Model 70-type bolt stop and blade ejector. The primary extractor cam is at the base of the bolt handle. The bolt cocks on opening, and the rear bolt shroud is used as the cocking piece.

The bolt handle is straight and rather short, but the comfortable, small ball operating end ensures a smooth and trouble-free cycling action. A Mauser action is intended to be worked vigorously. The micro-Mauser is no different—with the added benefit of its compact size being a shorter pull length to cycle the action.

“One crucial improvement with the CZ Mauser is its square bridge design, which allows for an integral scope base. The CZ rings mate up right to the action for solid attachment and help ensure reliable scope zeroes.”

The whole package came together when the SIG Sauer SRD762-QD suppressor was mounted on the CZ 527 SR via the SIG Sauer Taper-Lok mounting system. That is, after all, the point of a rifle chambered in 300 BLK—suppressor use.

The dimensions of the SRD762-QD are a weight of 17 ounces, a length and width of 7 inches and 1.625 inches, respectively, and a sound rating of 140 dB. The SRD762-QD is rated for .300 Win. Mag. usage. The subsonic 300 BLK rounds were “movie-quiet” out of the CZ 527 SR with the SIG suppressor mounted. The SIG Sauer Horseshoe Dot reticle allows for both supersonic and subsonic aiming points to be established.

The CZ 527 sports a unique, single-set trigger design. This definitively European feature might surprise U.S. shooters, but it proved useful when firing from the bench.

Under normal shooting conditions, the trigger can be used like any other trigger. When a higher level of
accuracy is desired, the trigger can be “set” for a lighter pull and super-crisp break. The trigger is set by pushing it forward, and it offers a trigger weight of 2 pounds. However, the normal trigger pull was a quite-acceptable, crisp 4.5 pounds and was certainly no detriment during accuracy testing at the range. The standard trigger is adjustable for pull weight, creep and overtravel. The set trigger is adjustable for weight only.


The CZ 527 American Suppressor Ready bolt-action, combined with the 300 BLK, makes for a very appealing, distinctive combination. There’s no need for a super-magnum rifle with a mega-zoom scope with a hyper-complicated reticle. I find it hard to believe that anyone using the CZ 527 SR 300 BLK is ever under-gunned or at a disadvantage when hunting deer-sized game or pressed into a defensive posture. I believe it will find a niche for itself in the American market. It will appeal to rifle lovers for its efficiency.

The users already familiar with the 300 BLK cartridge will appreciate the performance enhancement offered with the CZ 527 SR in terms of accuracy and ease of suppression.


The SIG Sauer Silencer Division was formally created in 2014, with its major introduction to the shooting public taking place at the 2015 SHOT Show. SIG Sauer had entered the suppressor market earlier but decided that a formal, distinct division (headed by industry veterans Kevin Brittingham, founder of AAC, and Ethan Lessard) would be the better path. Kevin and Ethan’s experience, combined with the manufacturing resources of SIG  Sauer, has proved to be a wise decision: Suppressor use has never been as popular for military, law enforcement and civilians. The benefits of suppressor use are hard to argue against.

The SIG Sauer Taper-Lok muzzle device that fits to a weapon’s threaded muzzle allows for other SIG muzzle devices to be mounted. Tapers on key surfaces provide self-centering for accuracy. (Photo: SIG Sauer)

The SIG Sauer difference really shines through when we move to discussing rifle suppressors. Through a revolutionary baffle design and unique manufacturing processes, SIG Sauer has eliminated the outer tube shell
found in other rifle silencers. SIG Sauer utilizes 100 percent circumferential welds combined with wire electronic discharge machining (EDM) the pathway of the projectile. In addition to reducing weight, this tubeless design increases volume, thereby lowering pressure and temperature for greater durability and increased signature reduction. Each of these benefits sets SIG Sauer suppressors apart.

The SRD762-QD suppressor. Thanks to its quick-detach feature, it can move seamlessly between rifles and is adaptable to multiple calibers up to .300 Win. Mag. (Photo: SIG Sauer)

SIG further pushed the envelope by using the best metals and coatings (physical vapor deposition [PVD] finish) combined with a superior mounting system—either direct-thread or quick-detach. PVD is more resistant to heat
and is scratch resistant. Inconel 718 (a mixture of stainless steel and nickel alloy) is used to withstand the punishment of mounting suppressors to short-barreled rifles and high round counts. Titanium is also offered as an option for users requiring even more weight-shaving from their suppressors. For SIG’s rifle suppressors, a Taper-Lok Fast-Attach System was created, enabling quick and simple installation of a muzzle adapter device; this
eliminates the need for shims. The SIG Sauer design optimizes alignment, improving accuracy and greatly reducing point-of-impact (POI) shift, even after multiple install/removal cycles. The Taper-Lok system allows users to access a variety of muzzle brakes and flash hiders for their rifles, all the while enabling SIG rifle suppressors to attach when needed.

The Taper-Lok mounting method for the rifle suppressor is an exclusive SIG Sauer feature. This innovative, three-piece system is built for speed, accuracy and repeatability over time. It is a modular design that allows for simple and economical changes to your muzzle configuration. (Photo: SIG Sauer)

The Taper-Lok Fast-Attach System reduces point-of-impact shift and increases repeatability by using tapered surfaces to self-center the suppressor during installation. The design also eliminates tolerance stacking, resulting in some of the most secure, reliable and accurate rifle mounts available. All SIG muzzle devices and suppressors are backward-compatible to traditional 90-degree shouldered firearms found outside the SIG weapon lineup. Hand pressure is all that is needed to secure or remove the SIG suppressor. Silencer removal requires 20 percent more force than does attachment, preventing any loosening during shooting. The Taper-Lok system contributes to the adaptability of the SIG rifle suppressors to more than one platform. By investing in multiple Taper-Lok muzzle devices, the user can move a suppressor between rifles.

A variety of muzzle brake and flash hider options is available from SIG Sauer. (Photo: SIG Sauer)

Basically, if the bullet diameter is .30 caliber or under, the SRD762-QD can be used. Of course, make sure to verify with SIG Sauer if any “exotic” calibers or applications are being contemplated. The limiting factor is getting the Taper-Lok muzzle device mounted to your barrel. The SIG Sauer Taper-Lok is not only an ingenious mounting system for the suppressor body, it is also an effective flash hider or muzzle device in its own right.

The Taper-Lok muzzle mount with one of the available muzzle devices installed (Photo: SIG Sauer)

Actual sound-reduction differences among most respected suppressors are small. More important is durability, especially if high-volume firing is expected. Maintaining zero and accuracy when installed, removed and then
reinstalled is paramount. Along these same lines, many users will appreciate the flexibility of being able to move a suppressor between platforms while still maintaining all the above-listed characteristics. The SIG Sauer suppressors succeed in surpassing all expectations, no matter the criteria used to judge—sound reduction, durability, accuracy and flexibility. This is a credit to their design and the real-world experience found in the SIG Sauer Silencer Division team.

The subsonic 300 BLK and a quality suppressor such as the SIG Sauer SRD762-QD make a potent combination.

In terms of quietness, nothing compares to a bolt-action firing subsonic ammunition with a quality suppressor attached. I was quite surprised by the accuracy premium offered by the bolt-action CZ 527 SR combined with SIG Sauer optics. The CZ 527 SR was tested from the bench for accuracy and from around barricades and other obstacles to get a better appreciation of its handling and performance. The suppressor was mounted at various times. Steel targets were smacked with ease out to 250 yards, either standing or using field-expedient rests.
While by no means rivaling a semiautomatic for fire power, the detachable, five-round magazines were handy to recharge the CZ 527 after the last round. As expected from a bolt-action, no malfunctions were experienced.
The safety selector was different, compared to U.S.-based rifles, with the safety engaged by pushing it forward and releasing it by moving it rearward. The safety made no audible noise when manipulating it—an important consideration for hunting or defense. With nearly 150 rounds fired, recoil was not a factor, and I experienced no issues or detriment to accuracy.



Velocity (fps)


Accuracy (inches)



Black Hills 124-grain OTM

2,210 1.5 1.0
Hornady 125-grain HP 2,335 1.66


SIG Sauer Elite 125-grain

2,220 1.33


Black Hills 220-grain OTM

1,010 1.75


SIG Sauer Elite 220-grain 995 1.25


NOTES: Velocity was an average of five shots using an RCBS AmmoMaster chronograph set up 10 feet in front of the muzzle. Accuracy is averaged from three five-shot groups at 100 yards.


The CZ 527 SR is a rifle that can serve in multiple roles—sport, hunting or defense. The 300 BLK chambering is a positive. It offers both performance and flexibility in adapting to a variety of situations. More and more load options are coming on line for the 300 BLK, including premium hunting bullets. The CZ 527 SR can serve in its own right or in combination with a high-capacity AR variant chambered in 300 BLK for defensive purposes.
It would not be unrealistic to imagine the CZ 527 SR in an urban sniper role. The suppressibility of the CZ 527 SR, thanks to factory subsonic loads, makes it ideal for shooting in a populated environment, which is perfect for law enforcement or animal control. Sixty yards out, shots from the CZ 527 SR would be undetectable, except for the subsonic, 220-grain round smacking the target.

“The CZ 527 action is a true micro-Mauser, not a standard Mauser action that has been chopped and re-welded. This makes for a svelte-handling rifle.”

A mounted suppressor not only limits noise, it also eliminates muzzle blast signature so as not to give away position. With the ability to attract users from a variety of backgrounds, the CZ 527 American Suppressor Ready should prove a popular offering from CZ-USA.



ACTION: Mauser bolt-action
CALIBER: .300 Blackout (tested) and 7.62×39
BARREL: 16.25 inches
WEIGHT: 5.9 pounds
SIGHTS: Integrated 16mm scope bases (squarebridge
Mauser) with 1-inch or 30mm rings available
STOCK: Black polymer, American-style pattern
CAPACITY: Detachable five-round magazine
MSRP: $748








Editor’s note: A version of this article first appeared in the October 2018 print issue of Gun World Magazine.