Anyone pricing an MP5 clone runs into the same question within ten minutes. A plain blowback 9mm pistol with a 30-round magazine costs a fraction of an HK SP5, and even the Turkish clones sit well above most AR9s. All of these guns fire the same cartridge from a barrel of roughly the same length. The difference is inside the receiver, where two small steel rollers hold the bolt shut for a moment after the shot. Most of what you pay for in an MP5 clone, and most of what you put up with, comes from those rollers.
How two rollers delay the bolt
A straight blowback gun has no lock at all. The bolt is held against the cartridge by its own weight and a spring, and the only thing slowing it down when the case pushes back is inertia. That works in 9mm, but only with a heavy bolt and a stiff spring, which is why blowback carbines feel like they hit twice: once when the bolt slams back and again when it slams home.
The MP5 splits the bolt in two. A light bolt head sits up front and carries two rollers. Behind it is a heavier bolt carrier with a wedge-shaped locking piece in its nose. When the gun is in battery, the locking piece pushes the rollers outward into recesses cut in the barrel extension. On firing, the case pushes the bolt head back, but the head cannot move until the rollers fold inward, and they can only fold inward by shoving the locking piece, and with it the whole carrier, rearward. The angles are cut so the carrier has to travel about four times as fast as the head. The heavy part does most of the moving while the light part barely creeps, and by the time the rollers have fully cleared their recesses, chamber pressure has fallen.
Invalid Date
More Articles
The design depends on two further details. The chamber is fluted: shallow grooves run along its front to ease extraction, because the bolt starts opening while the brass is still pressed against the chamber wall. And the gun fires from a closed bolt, so nothing heavy moves between the trigger press and the shot.
The idea is older than the MP5. Mauser engineers built roller-delayed rifles in the last months of the Second World War. After the war Ludwig Vorgrimler took the idea to Spain, where it became the CETME rifle, and Heckler & Koch turned the CETME into the G3 in the late 1950s. The MP5 is the G3 scaled down to 9mm. HK designed it between 1964 and 1966 under the name HK54, and West German border police and army special units adopted it in 1966 as the MP64 before it was renamed.
What it buys you
The main gain is a softer, later impulse. Because the rollers do the delaying, the bolt group can be lighter than a straight blowback bolt, the recoil comes as a push, and the gun stays flatter through a string of shots. That feel is what the platform's following is built on.
There is also no gas system. With no port, piston or tube, the barrel stays fixed, nothing taps gas off the bore, and the action does not care much about barrel length, so the same system runs in an SP5K with a 4.53in barrel and an SP5L with a 16.57in one.
The timing can be tuned, too. The angle on the locking piece sets how long the delay lasts, and HK fits different locking pieces to the standard gun, the short K models and the suppressed SD models, because a suppressor raises back-pressure. A straight blowback gun has only bolt weight and spring rate to adjust. And since the gun fires from a closed bolt, it sits still at the moment of the shot.
What it costs you
Start with the brass. The fluted chamber leaves soot stripes along every case, and the ejector throws empties a long way forward and to the right, which handloaders and whoever is standing in the next lane both notice.
Then there is bolt gap, the space between the bolt head and the carrier with the gun in battery. Owners measure it with a feeler gauge, it closes up as the rollers and their recesses wear, and the fix is a set of oversized rollers. Blowback guns have no equivalent check.
Parts come from their own supply chain. Stamped steel receivers, welded trunnions and HK-pattern trigger groups have nothing in common with the AR world, so even with curved MP5 magazines easy to find, a clone cannot be built up from commodity parts.
Finally, weight and price. The SP5 weighs 5.1 lb unloaded, heavy for a pistol, and every roller-delayed 9mm on this list is priced above the common AR9s.
Straight blowback 9mm
Roller-delayed (MP5 pattern)
What holds the bolt shut
Bolt weight and spring
Rollers plus a heavier carrier
Felt impulse
Sharper, two-stage
Softer, later
Barrel and gas
Fixed barrel, no gas system
Fixed barrel, no gas system
Chamber
Plain
Fluted
Routine check
Spring wear
Bolt gap
Suppressor tuning
Bolt weight, spring
Locking piece angle
The same gun built both ways
The cleanest way to see what the rollers are worth comes from a gun that is no MP5. Grand Power in Slovakia sells the Stribog SP9A1 as a straight blowback 9mm, and the SP9A3 with a roller-delayed bolt inside a receiver that looks almost identical from the outside. Grand Power designed the A3 roller arrangement itself, without copying HK's layout, for the same purpose. Reviewers who shot both describe the A3 as softer and report less gas in the face when suppressed. Grand Power built the A3 family in 9mm, 10mm and .45 ACP, and the SP9A3G version takes Glock magazines.
For a buyer weighing whether roller delay is worth the money, handling the two Stribogs side by side is about as close to a controlled comparison as a gun shop offers.
Who builds an MP5 clone
Semi-automatic MP5s have been sold in the United States since HK imported the HK94 carbine from 1983 to 1989 and the SP89 pistol from 1989 to 1994. Between the SP89 and the SP5, which HK introduced at the end of 2019, the civilian market ran on clones. The guns below are the ones in production, grouped by who makes them. Barrel lengths are taken from the listings in this catalog.
Maker
Models
Built in
Barrel lengths
Heckler & Koch
SP5, SP5K, SP5K-PDW, SP5L
Germany
8.86, 4.53, 5.83, 16.57in
Century Arms (made by MKE)
AP5, AP5-P, AP5-M, AP5-SD, AP5-L
Turkey
8.9, 5.75, 4.5, 5.75, 16.5in
Zenith Firearms
ZF-5, ZF-5P, ZF-5K, ZF-5T
Virginia
8.9, 5.8, 4.6, 5in
PTR Industries
9CT, 9KT, 9RS, 9R
South Carolina
8.86, 5.16, 5.83, 16.2in
Military Armament Corp
MAC 5, MAC 5K
Turkey
8.9, 5.8in
HK makes the SP5 in Germany. Its suffixes follow the military guns: K is the short MP5K pattern, PDW is the K with a longer barrel, and L is a 16.57in barrel on a gun that still ships without a stock, so it is a 25.5in pistol rather than a rifle.
Turkey's state arms maker MKE builds MP5s under HK license, and the AP5 is that production sold to US civilians. The AP5-P is the MP5K pattern, the AP5-M is a shorter micro version, and the AP5-SD wears a faux suppressor shroud.
Zenith Firearms imported the same MKE guns as the Z-5 series until the two companies split at the end of 2020, at which point Century took over the import. Zenith then started building its own ZF-5 in Virginia. An older listing that says Z-5 and MKE is the Turkish gun; ZF-5 is the American one.
PTR Industries in Aynor, South Carolina, already built G3 rifles when it introduced the 9C and 9CT pistols at SHOT Show 2018. The CT is the full-size pistol, the KT the short one, and the R a 16in carbine.
Military Armament Corp is a brand of the importer SDS Arms, and the MAC 5 and MAC 5K come from a Turkish factory that the company does not name. Reviewers have compared it closely with the AP5, but the two come from different plants.
Browse current listings on the MP5 clones page, HK's own guns on the MP5 page, and the Century family on Century Arms AP5.
Lookalikes that do not have rollers
The MP5 shape is popular enough that several guns copy the outside and skip the mechanism.
Gun
Caliber
Operation
What it shares with the MP5
GSG-16
.22 LR
Straight blowback
Shape, stock, handguard
HK MP5 .22 LR (built by Walther)
.22 LR
Blowback
Shape and controls, under HK license
MAC IX
9mm
Direct blowback
Takes MP5 magazines
Panzer Arms HAN9
9mm
Blowback
Takes MP5 magazines
The two rimfires are trainers. They copy the controls closely enough to practice the manual of arms, and a .22 LR has no use for a delayed action. The two 9mm guns are the ones to watch for: both are sold on their MP5 magazine compatibility, and "MP5 mags" in a listing describes the magazine well and says nothing about the action.
The bigger roller-delayed family
The MP5 is the small end of a family that started with rifles, and most of the makers above build the larger guns too.
Line
Caliber
Format
PTR 91
.308 Win
Rifles, 16 and 18in barrels
PTR PDWR and K3P
.308 Win
Pistols, 8.5 and 12.5in barrels
PTR 32
7.62x39
Rifle and pistols, takes AK magazines
Century C308 and C93
.308 Win, .223 Rem
Rifles
Century AP51 and AP53
7.62x51, 5.56
Pistols, 8.3in barrels
Zenith ZF-56 and ZF-300
5.56, .300 Blackout
Rifles and pistols
Grand Power Stribog A3
9mm, 10mm, .45 ACP
Pistols and carbines
PTR's rifles trace back to G3 tooling and drawings that its predecessor, JLD Enterprises, bought from Portugal's state arms factory, which had built the G3 under HK license. In .308 the trade-offs grow with the cartridge. The rifles are heavy (the PTR-91 A3SK weighs 9.3 lb with a 16in barrel) and the fluted chamber throws .308 brass hard.
Reading an MP5 clone listing
The model suffix carries most of the information, and the barrel length is the fastest way to check it. An SP5 has an 8.86in barrel; 4.53in means an SP5K, 5.83in an SP5K-PDW and 16.57in an SP5L. For Century, 8.9in is the full-size AP5, 5.75in the AP5-P or AP5-SD, and 4.5in the AP5-M.
Check the suffix against the barrel before trusting the title. This catalog held an SP5K and two SP5Ls titled as plain SP5s, one of them described as a carbine with an adjustable stock that it does not have, and a second SP5K described as an SP5 throughout. The catalog also titled two AP5-Ms as full-size AP5s, and one carried the full-size weight. The PTR-91 A3SK appeared three times at 4.22 lb, for a rifle that weighs 9.3. A MAC 5 was described as plain blowback, two descriptions called the system roller-locked (that is the MG42, a different mechanism), and a ZF-5 listing said the American-built gun was made in Turkey. All of those have been corrected, and the HK-made SP5 variants that were missing from the MP5 page have been added to it.
Then look for the words that show the rollers are there: roller-delayed blowback and a fluted chamber. If a gun takes MP5 magazines but the description says blowback, it is an MP5-shaped carbine, and it will shoot like any other blowback 9mm.
Nick Sawinyh - Nick Sawinyh is a father, husband, hobby farmer, and gun enthusiast from Kentucky. He founded GunsNation and writes most of what appears on this blog.
