A faithful reproduction of H&K’s original MP5, the Century Arms AP53 pistol in 5.56mm is a willing platform for do-it-your-way upgrades
by Jeremy D Clough
The best time to start collecting roller lock parts was about ten years ago. The best time to get into the guns is now.
For years, various importation regulations limited the form in which even semi-auto copies of the classic HK designs like the G3 and MP5 could be imported. Most significantly, the push-pin trigger housing of the machine guns was verboten, and paddle mag catches, which rotate around the front push-pin hole, were similarly prohibited to ensure a machine-gun trigger housing couldn’t be retrofitted to the gun. This isn’t just about aesthetics: pushbutton mag catches were required instead and they were wretched, making mag changes into grip changes and the whole process glacially slow.
The current era is a bit of a golden one: paddle mag catches (at least installed via some processes) are now legal, and the addition of a couple extra semi-auto-only features results in the legal importation of push-pin lower guns that come complete with all the looks and coolness of the originals.
And this brings us to the Century Arms AP53, a 5.56mm variant of its successful 9mm AP5 clone of the MP5.
The HK53 dates back to the 1960s, when the now-ubiquitous shorty .223 rifles were not, as they say, “a thing,” and was based on the earlier HK33. Developed to compete in the U.S. SAWS trial ultimately won by the M16 (which had already been adopted), the HK33 is a scaled down G3 battle rifle in 5.56mm with a nominal 15 1/2-inch barrel. The 43 and 93 variants followed for the civilian market, as did a 12.69-inch version called the 33K developed for decidedly non-civilian users. Even that short size — which is analogous to the G3K .308 developed at the request of the SAS — still wasn’t quite short enough for some. About four inches less barrel later came the HK53.
At times unhelpfully referred to as a submachine gun (in common usage, subguns fire pistol calibers), the HK53 is the same basic size as the 9mm MP5, providing a serious increase in power with all the modularity that makes the 90-series guns so flexible.
Since 1999, it’s been produced under license in Turkey by Makine ve Kimya Endustrisi (MKE for us), which also makes licensed copies of the MP5 and the G3. While .308 roller locks (and in the past several years, 9mms) have long been fairly accessible, .223 versions are generally in short supply in the US, which makes me especially happy that Century Arms has begun importing MKE’s semi-auto AP53.
You’d be forgiven for thinking it was the military version MKE makes. Opening the slender, appropriately-sized hardcase reveals a dead ringer for a full auto HK53, down to the four-position pictogram trigger housing. The only giveaway is the buffer tube-style Magpul arm brace in place of a buttstock — and the fact that the selector lever for the semi-auto-only trigger pack only moves to the “safe” and “single” positions. The case also includes a cleaning kit, HK-style 3-position sling, and two 30-round magazines. Reminiscent of others made by HK and SIG, the translucent magazines have a stud arrangement that lets them clamp together, doing away with the need for an expensive separate clamp.
The AP53 receiver comes equipped for the traditional claw-style optic mounting system. Unlike tall HK claw mounts, the included Picatinny rail mount has four wedges that are screwed in once the mount is laid in place on the top of the gun. To this, I added Holosun’s HE530G-RD.
Made from Grade 5 titanium, the HE530 is available with a green, gold, or red (my choice) multi-reticle system featuring a 2 MOA dot or 65 MOA ring/dot and weighs 10 ounces on my postal scale. It came with front and rear flip-down lens covers and an integrated killflash. The Holosun comes with a locking QD throw lever mount that still allows you to see the factory iron sights beneath the optic. Aided by a shake-awake function, battery life can stretch to 50,000 hours. I haven’t turned it off since it arrived.
So, how does it shoot? Unbelievably good. Century provided a 450-round battle pack of MKE 62-grain SS109 5.56, and Fiocchi provided its new 77-grain .223 SBR load, the .308 version of which has greatly impressed me. To this I added some Black Hills ammo I had on hand, including their 77-grain tipped MatchKing load, for a total count of over 550 rounds.
I didn’t clean the AP53, I didn’t oil it, and it didn’t give me a reason to. There were zero malfunctions of any kind, and it ran well with both the factory translucent magazines and a 30-round steel HK magazine that I added into the mix. The trigger broke at an average 8 pounds, 6 ounces on my Lyman digital scale — about right for a military-style trigger, with the expected amount of roll.
At fifteen yards, shooting fairly quickly with irons, I was able to put a magazine into a roughly fist-sized group. I did the same at 25 yards with the Holosun, taking time to center the dot for each shot. From the bench, using a Ransom Rifle Master front rest and Armageddon rear bag, I shot into 3/4 inches at 25 yards and managed a best 3-shot group of 2.5 inches at 100 yards — more than acceptable for the pistol version of a platform where 3 MOA is considered sniper grade. Had I used an LPVO or traditional riflescope instead of a dot, I expect even better groups, but this is an 8-inch pistol, not a target rifle. Even so, I was able to hit clay pigeons on the 100-yard berm from a standing position both with irons (though I had to line them up with the top left corner of the front sight blade) and with the Holosun.
The Fiocchi load logged a ten-round average of 2,442 fps from a 16-inch AR, 2,264 fps from my 11.5-inch AR SBR, and 2,076 fps from the AP53’s 8.3-inch cold hammer forged barrel, while MKE ball posted a surprisingly warm 2,412 fps.
I have but a single complaint about the AP53, and that is the four-prong flash hider, aka the Tuning Fork of Doom. Reminiscent of the earliest M16 muzzle devices, it’s both historically accurate and quite effective, but imparts a long-lasting ring to each shot fired, which sounds disturbingly like that tinnitus most of us have been working on for a few decades. With time, you do adjust to it, but eliminating it is preferable.
Since I’ve been working with Dead Air’s hard-use Sandman X suppressor, I removed the four-prong hider (being careful to pry back the locking ring as I did so) to install a Xeno mount. If you intend to apply for a Form 1 to make the AP53 an SBR, now is the time to measure the barrel, which must be done with any muzzle devices removed. And hang on to that thought, because we’ll be doing just that with this one, and will cover the process in an upcoming article.
The AP53’s faithful barrel contour tapers back from the muzzle thread rather than having a square shoulder. That makes it a little more complicated to suppress because some sort of standoff is required to ensure the device and suppressor mount square to the muzzle. I purchased KAK’s AP53 Taper Adapter and installed it before torquing on the Dead Air device.
Word to the wise: I use a set of contoured wooden vise blocks to clamp the front sight tower in place before installing/removing muzzle devices on roller locks. But be cautious with the amount of torque applied, as over torquing it — as I did when trying to clock the flash hider to my satisfaction — can lead to serious issues.
After swapping out the Sandman X’s .30 caliber endcap for a .223 cap and checking the assembly with a Geiselle Superior Alignment Gage, it was back to the range for a little suppressed tryout. While roller locks often need a different locking piece for suppressed fire, the AP53 functioned equally well with or without the Sandman both with the MKE and Black Hills’ tipped 77 MK load, and I could not tell a difference in either recoil or ejection pattern, although point-of-impact changed.
All in all, the AP53 is faithful in every sense — not only is it a faithful copy of the HK53, it has the field-plowing reliability for which roller locks are known. And it’s going to be a great base gun for more customizing, so stay tuned…
- TESTED: Century Arms’ AP53 5.56mm Pistol - March 2, 2026
- HUSH 101: Suppressor Basics - January 9, 2026
- Modifying Century Arms’ WASR AK - October 29, 2025
