The 5.7x28mm "Cop Killer" Cartridge Myth

By Barr H. Soltis with Chuck Hawks

As a U.S. Government intelligence manager, I receive a significant number of "Officer Safety" alerts generated by a wide variety of local, state and federal law enforcement agencies. One alert that regularly rears its ugly head focuses on the alleged "cop killer" 5.7x28mm round fired by the Five-seveN pistol manufactured by Fabrique Nationale de Herstal (FNH) of Belgium. Given my innate curiosity, I decided to research this super duper cop-killing round and try to put it into perspective.

This is a .224 caliber rimless, bottlenecked, boxer primed, centerfire cartridge designed for use in semi-automatic arms. (Primarily pistols and sub-machineguns.) The cartridge overall length is 1.594 inches and it can be loaded to a maximum pressure of 50,040 psi.

Published reports indicate that as factory loaded the 5.7x28mm drives a 32 grain bullet, load #SS190-AP (armor piercing), at a muzzle velocity (MV) of 2350 fps with 390 ft. lbs. of muzzle energy (ME). The 28 grain spitzer bullet, load #SS195LF-JHP, has a muzzle velocity of 2350 fps and muzzle energy of 290 ft. lbs. The 40 grain Hornady V-Max bullet, load #SS197SR, claims a muzzle velocity of 1950 fps with 340 ft. lbs. of muzzle energy. Readers old enough to remember the obsolete .22 Remington Jet small game and varmint cartridge of 1960--40 grain bullet at about 2000 fps from a S&W Model 53 revolver--will be startled to hear that the slightly less powerful 5.7x28mm is a "cop-killer" round.

It is important to remember that the 5.7x28mm velocity and energy figures were derived from a 10.35 inch (sub-machinegun length) test barrel and that the Five-seveN pistol barrel actually measures 4.82 inches in length. Realistically, we can anticipate a substantial velocity loss of about 20% when the 5.7x28mm cartridge is fired from a pistol. This would mean an actual MV of approximately 1560 fps and ME of 216 ft. lbs. for the 5.7x28mm 40 grain bullet when fired from a handgun. Because it starts a heavier bullet at lower velocity, which maximizes energy and minimizes velocity loss, this should be the most effective load for a 5.7x28mm pistol.

A comparison of the performance of the .22 Winchester Magnum Rimfire (WMR), introduced in 1959, and the 5.7x28mm is interesting. The .22 WMR shares the same bullet diameter (.224") as the 5.7x28mm cartridge and their muzzle and energy figures are actually rather similar.

Winchester's Supreme .22 WMR loaded with a 34 grain jacketed hollow point bullet has a muzzle velocity of 2120 fps and muzzle energy of 339 ft. lbs. from a (presumably 24") rifle barrel and a muzzle velocity of 1690 fps with 216 ft. lbs. of muzzle energy from a 6.5" pistol barrel. (That is just a hair over the 20% velocity loss that we postulated for the 5.7x28mm.)

Winchester's Super-X .22 WMR 40 grain jacketed hollow point (JHP) and full metal jacket (FMJ) bullets--Winchester offers both--have a MV of 1910 fps with ME of 324 ft. lbs. from a rifle barrel. Fired from a 6.5" pistol barrel the same loads register 1480 fps MV and 195 ft. lbs. ME. Note that rifle ballistics of this load are nearly identical to the 40 grain 5.7x28mm factory load as fired from a sub-machinegun length barrel and from a pistol barrel the 5.7x28mm is only a puny 21 ft. lbs. of kinetic energy ahead of the .22 WMR. I have never heard that semi-automatic .22 WMR squirrel and jackrabbit rifles were considered a particular threat to police, nor have I ever heard the .22 WMR described as a "cop killer" handgun round. Actually, the .22 WMR is considered a "mouse gun" caliber by most handgun authorities.

Another interesting comparison is with the 9x19mm (9mm Luger) cartridge. The 9x19 is the official NATO pistol and sub-machinegun cartridge and is widely used by police as well as by at least some real life criminals. Using Winchester published ballistics for comparison, we find that the popular Super-X 115 grain Silvertip JHP load has a MV of 1225 fps and ME of 383 ft. lbs. from a 4" pistol barrel. The U.S. military load for the 9x19mm drives a 124 grain bullet at a MV of 1299 fps and ME of 465 ft. lbs. from the Beretta M9 service pistol.

These numbers indicate that the common 9x19mm is a considerably more powerful cartridge than the 5.7x28mm when fired from pistol length barrels. This will surprise no one familiar with firearms or who has a passing familiarity with external ballistics. In reality, because the 9x19 fires a heavier bullet with far greater cross-sectional area, it will create a much larger wound cavity and prove far deadlier than this simple comparison of "paper" ballistics would indicate.

The 5.7x28mm caused quite a stir a few years back with the assertion that its AP load could penetrate at least some Kevlar helmets and body armor. (So, of course, will most other AP rifle and handgun rounds.) This may or may not be true, but the fact is that sales of armor piercing ammo are restricted to law enforcement and the military. This alone makes the 5.7x28mm cop killing round nothing more than an urban legend, leaving the practical use of the 5.7x28mm for target shooting, plinking and short range varmint hunting, much like the .22 WMR.

Frankly, I know of few individuals who would be willing to spend more than $900.00 for the FN Five-seveN pistol and then shell out more than $20 for a 50 round box of ammunition. (.22 WMR ammo commonly sells for $7-$8 for a 50 round box.) I imagine that the Five-seveN probably also fails to spark much interest with criminals, as these pistols are rare and thus almost impossible to acquire except from legitimate, FFL dealers. Typically, the criminal element usually relies on the availability of larger (9x19mm, for instance), more effective calibers that can be easily acquired in the stolen gun market.

This leaves us with the obvious conclusion that the 5.7x28mm cartridge has little advantage over the .22 WMR in terms of killing power and serious disadvantages in terms of the price and availability of both firearms and ammunition. Without doubt, being shot with either can have deadly results, but there are much greater threats and more important things with which to be concerned. The top "man stopping" handgun cartridge remains the .357 Magnum, and it has been around since 1934.

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Copyright 2008, 2014 by Barr H. Soltis and/or All rights reserved.