FK BRNO Field Pistol: The 7.5 FK Story

Why was the 7.5 FK developed?

Keith Wood of American Rifleman writes that the security company needed a secondary weapon to fill the gap between its 5.56x45mm NATO carbines and its 9mm handguns, for the 50- to 100-meter engagements common in its area of operations, and nothing it could find met all of its requirements. Those requirements, as Wood lists them, were a group of 4 inches or less at 100 meters, a caliber of at least 7.2mm, 1,475 feet per second at 100 meters, and recoil no worse than a .45 ACP M1911. The plan was to fit the new cartridge into an existing pistol design with a folding stock.

FK BRNO’s design team produced the 7.5 FK. By the time it was working, the contract was over and the client had lost interest. FK BRNO kept the project and adapted it for civilian sporting use. The one requirement it could not meet was fitting the round into an existing handgun: the pressures were too high, so the company designed a pistol around it.

The 7.5 FK cartridge

The 7.5 FK is a bottleneck round with no parent case. Wood gives the overall length as 35mm under CIP specifications and suggests 7.5x27mm as a fair name, after the case length. The 95-grain solid-copper hollow point leaves the muzzle at an advertised 2,000 feet per second, about 844 foot-pounds, and is still doing about 1,525 feet per second at 100 meters. Wood’s own test averaged 2,007 feet per second. Wood reports an operating pressure of about 50,570 psi and describes the pressure as nearly on par with the .223 Remington, too high for any existing handgun design.

How the FK BRNO Field Pistol is built

FK BRNO is Czech, and the Field Pistol follows the CZ 75 layout: the slide rides inside the frame rails rather than over them. According to Wood, the designers tried roller-locked, gas-operated, delayed-blowback and rotating-barrel designs before settling on a linkless tilting barrel, similar in principle to the Browning High Power. The result is a locked-breech, short-recoil, single-action semi-automatic.

Everything except parts such as springs and grips is machined from solid steel billet, with no stampings, castings or metal-injection-molded parts, and the steel is black-nitrided. The Field Pistol has a frame-mounted thumb safety on the left and feeds from steel magazines rated at 15 or 10 rounds; TFB’s reviewer could load no more than twelve into his 15-round test magazine and put it down to a stiff new spring. We have not tested ours. TFB lists the weight at 1,300 grams, about 46 ounces unloaded, and the barrel at 152mm, or six inches.

The reviewers differ on the trigger. Wood measured a consistent 3 lbs., 8 oz. break on his test gun but with repeatable creep, the one disappointment in his review; TFB’s reviewer called it one of the smoothest handgun triggers he had pulled in decades.

The counterweight under the barrel

Look under the barrel and the frame runs all the way to the muzzle. Inside, a cylindrical counterweight rides on the guide rod. Shooting Illustrated describes it as wrapping around the recoil spring and guide rod. TFB explains the idea: the pistol’s center of mass sits farther forward than usual, and the counterweight is meant to reduce perceived recoil. Wood credits it, along with the locking system, with sending the recoil straight back and keeping muzzle rise down. TFB’s reviewer was more cautious: recoil was light and muzzle flip minimal, but he could not tell how much of that came from the counterweight and how much from the sheer weight of the gun.

The Butterfly rear sight

The Field Pistol can wear a conventional post and notch, a reflex sight mount, or FK’s own Butterfly Sight, which is what ours has. It pairs a red front bead with a skeletonized rear sight: a small center aperture between two cut-out wings, with a shallow V along the top edge. Wood describes the V as a secondary aiming point for long shots; in our video we put it as holding on the V at the top for distance.

Wood’s groups with the Butterfly were only so-so. He put that down to the rear aperture sitting too far from the eye on a handgun, and concluded the Butterfly was designed with the folding stock in mind; when he fitted the conventional sights that came with his test gun, his five-shot groups shrank by half, to about an inch at 25 yards. Other reviewers reported hits on steel at distance, a different test from paper groups: Shooting Illustrated rang steel at 110 yards, and TFB consistently hit a 12-by-12-inch steel target at 100 yards.

Was the FK BRNO Field Pistol ever issued?

Not that we could find: in the sources we reviewed, we found no army or police force that issued it. It began with a private contractor’s requirement and ended up a sporting pistol. Separately, American Rifleman reported in 2018 that only 1,001 Field Pistols were planned for the United States market.

How big is the FK BRNO Field Pistol?

TFB lists it at 240mm (9.5 inches) long with a 152mm barrel. Next to our owner’s carry gun, a CZ Shadow 2 Compact, the Field Pistol makes the CZ look tiny, as he puts it; the photo is a visual impression, not a measurement.

FK BRNO PSD vs. Field Pistol

FK later built the PSD. It keeps much of the Field Pistol’s steel top end on a polymer frame. FK BRNO lists it at 230mm (9.05 inches) long against the Field Pistol’s 240mm, with a 136mm (5.3-inch) barrel and a weight of 1,100 grams against 1,300. FK BRNO lists a second barrel for 10mm and .40 S&W as included, using the standard multi-caliber magazine, and a 9mm barrel as optional, with two 9mm magazines and a lighter spring. RECOIL’s review describes a tungsten counterweight between the slide and the guide rod that adds weight up front and spreads out the recoil impulse, and it notes that the polymer frame shifts the balance noticeably forward.

FK BRNO Field Pistol recoil

Our owner hasn’t fired the Field Pistol. He’d always heard it kicks hard. The reviews we read say the opposite. Wood found recoil “unexpectedly light” despite the velocity and pressure, and Shooting Illustrated compares it to a 1911 shooting a hot .45 ACP load, more comfortable than any 10mm semi-auto or .357 Magnum revolver.

His take: it’s a range toy that never found a real job. Think he’s wrong? Tell him what you’d use it for.

Specifications

Item	FK BRNO Field Pistol
Maker	FK BRNO, Czech Republic
Cartridge	7.5 FK, bottleneck, 27 mm case length
Bullet and velocity	95 gr copper hollow point, about 2,000 fps advertised
Action	Semi-automatic, short recoil, linkless tilting barrel, single action
Recoil system	Counterweight on the guide rod
Magazine	Steel, 15 or 10 rounds (nominal)
Construction	Machined from solid steel, black-nitrided
Barrel	152 mm (6 in)
Length	240 mm (9.5 in)
Weight	1,300 g (46 oz)
Sights	Butterfly aperture, post and notch, or optic mount

On the floor at OSA

The Field Pistol and the PSD in this article are part of the Old Steel Arsenal collection, and the CZ Shadow 2 Compact is our owner’s own carry gun; none of them is among the pieces linked below. These are related pistols in our case:

• A CZ 75 Pre-B from Czech police service, the Czech design whose slide-inside-the-frame layout the Field Pistol follows. Our guide on how to identify a CZ 75 Pre-B covers the early guns.
• A CZ 85 Pre-B transitional, a later member of the CZ 75 family.
• A 1979 FN Browning Hi Power two-tone and an FN Hi Power 9mm, the pistol American Rifleman compares the Field Pistol’s linkless tilting-barrel lockup to.
• A 1927 Czechoslovak CZ vz. 24, an earlier chapter of Czech pistol making.

The grid below updates by itself as pieces come and go.

The short version is on our Instagram. Watch it on Instagram.

General information for collectors, not legal advice. In the United States, fitting a shoulder stock to a pistol with a barrel this short, such as the folding stock the Butterfly was designed around, can create a short-barreled rifle under federal law.

Sources

• Keith Wood, American Rifleman, “Tested: The FK BRNO Field Pistol” — https://www.americanrifleman.org/content/tested-the-fk-brno-field-pistol/ (security company in the Middle East, 1,001 for the U.S., carbine-pistol gap, 50–100 m, requirements, contract ended, civilian adaptation, cartridge could not fit an existing pistol, 35 mm overall, 7.5×27 mm, 95 gr, 2,000 fps, 844 ft-lb, 1,525 fps at 100 m, 50,570 psi, CZ 75 slide-in-frame layout, mechanisms tried, linkless tilting barrel like the High Power, machined from billet, black nitride, single action, frame safety, counterweight, Butterfly sight and V, aperture and folding stock, SBR, measured 2,007 fps, trigger 3 lb 8 oz with creep, groups halved with conventional sights to 1 in at 25 yds, recoil unexpectedly light)
• Pete, The Firearm Blog, “TFB Review: The FK BRNO Field Pistol” — https://www.thefirearmblog.com/blog/2017/11/22/fk-brno-field-pistol/ (single action, tilting barrel, forward center of mass and counterweight, unclear how much of the light recoil is the counterweight versus the weight, twelve rounds in the 15-round test magazine, smooth trigger, 12-inch steel at 100 yards; length 240 mm, weight 1300 g, barrel 152 mm)
• Shooting Illustrated, “Range Review: FK Brno Field Pistol in 7.5 FK” — https://www.shootingillustrated.com/content/range-review-fk-brno-field-pistol-in-7-5-fk/ (counterweight around the recoil spring and guide rod; steel at 110 yards; recoil like a 1911 with a hot .45 ACP load, more comfortable than a 10 mm or .357 Magnum)
• FK BRNO, “PSD Pistol” — https://www.fkbrno.com/psd-pistol (136 mm barrel, 230 mm length, 1100 g, included 10 mm/.40 S&W barrel, optional 9 mm barrel with two magazines and a lighter spring)
• RECOIL, “FK BRNO PSD Review” — https://www.recoilweb.com/fk-brno-psd-review-165154.html (polymer frame, steel top end, tungsten counterweight, forward balance)