For a while now, photos of a very unusual AK-style rifle using an AR gas system have been making the rounds on social media sites, and we now know it’s real, courtesy of Polenar Tactical. A prototype design by Tinck Arms, the rifle doesn’t use a true direct impingement gas system, but a hybrid system using a remote short-stroke gas piston.
What Tinck Arms achieved with the combined gas systems is a free-floating barrel, to make an AK shoot without the characteristic barrel whip. And because the piston system is separated from the bolt carrier, it also produces noticeably reduced recoil.
Tinck Arms is a Slovenian company that some may recognize as the developers of the Perun family of firearms. The Perun is a modular platform loosely based on the AR-15 that uses proprietary self-contained upper receivers.
This modified AK is built on a Zastava M70 receiver, and it mostly uses AK components. It also has a large, modular handguard with M-Lok slots and an extended rail section for optics and accessories. The top rail continues back over the rear trunnion to place an optic closer to the rear without interfering with the dust cover.
With the handguard removed, it’s immediately obvious that this prototype is different. Instead of a large AK gas block and piston tube, the rifle has a typical low-profile AR gas block and standard AR gas tube.
The gas tube runs from the AR gas block to a secondary gas block at the barrel trunnion. The system uses two gas blocks, one to tap the barrel and the other to run the gun’s short-stroke piston system. The handguard and rail mount to the secondary gas block and the gap between the front trunnion and receiver.
The short-stroke piston completely replaces the long-stroke piston and doubles as a guide rod for the bolt carrier and action spring or recoil spring. There only look to be a small number of changes to the AK parts, and nothing that looks like it would be considered too permanent.
Aside from the cut-down bolt carrier and maybe a replacement trunnion for the AR-style barrel, the rest of the AK looks unchanged. Even the bolt is a standard AK bolt, although it’s hard to tell at a glance how the bolt, trunnion and barrel interface. However Tinck did it, it clearly works.
The prototype has a few other mods, including an AR stock tube adapter and quick-detach sling swivels in place of an underfolder-type stock. But those look cosmetic, not anything core to the design. It also uses either a modified or proprietary takedown button that locks into the piston assembly.
“As it is now, it already promises a couple of improvements to the AK system; lighter bolt carrier, which means less moving mass, less recoil and faster cycling,” said Ziga Polajnar. “Because of the gas impingement design, we can get a true free-floating barrel and no AK barrel whip.”
He also points out that since the prototype uses AR gas blocks, the design can accept common adjustable gas blocks. Tinck is also considering adapting it to a quick-change barrel system down the line.
For now, this is a proof of concept, but a solid-looking one just the same. For more videos like this, check out Polenar Tactical on YouTube.