The Tinck Arms Perun X-16 (distributed in the US by AEA Arms) is a much more interesting rifle than I expected from an initial glance. I assumed it would be just another AR-18 derivative, but the truth is much more interesting. Slovenian company Tinck Arms designed the Perun (named after a Slavic god of thunder) to be exceptionally modular - even moreso than an AR, dare I say it. It is also designed to use a lot of standard commercially available parts - AR barrels, gas blocks, bolts, gas tubes, lower receivers (some trimming required here), all AR lower components, and SCAR buttstocks. And yet, the rifle is more than an AR, with a clever gas system and a similarly modular upper assembly.

The gas system is similar to the Halloway HAC-7, but much more refined. It is a short stroke gas piston, but located over the chamber instead of at the gas block. A shortened AR gas tube leads from the (adjustable) gas block back to the upper receiver, thus reducing the amount of reciprocating mass and keeping that mass closed to the center of the rifle. This improves balance over other piston AR type rifles, and it also reduces potential muzzle climb.

Disassembly is exceptionally quick and simple, as is reconfiguring the rifle to different layouts. Since the bolt, barrel, and gas block are all straight AR parts, builds in hipster calibers like 6.5 Grendel, 6.5 ARC, 224 Valkyrie, or whatever new flavor you like are easy to do. Standard factory options are 5.56 and .300 Blackout in the US, plus some additional options in Europe. Note that the lower on the Slovenian version is different than that of the US version. These are imported into the US simply as uppers, and mated to domestic production AR lowers here.