Halcyon Defense .277 Wolverine Tantal Conversion

Hrachya H
by Hrachya H
Halcyon Defense .277 Wolverine Tantal Conversion (11)

Halcyon Defense is a new company founded by Daniel Fisher, one of the engineers behind many KNS Precision products. This company is specialized in building custom firearms. They have several interesting ongoing projects and in this article, we’ll talk about one of them – AK rifle (Polish Tantal) chambered in .277 Wolverine.

L-R: .223 Remington, .277 Wolverine, .300 Blackout, 6.8 SPC

The .277 Wolverine is designed by Mad Dog Weapon Systems. It is a .270/6.8mm caliber cartridge based on a shortened .223 Remington case. This round fits standard AR-15 bolts, can be loaded in AR magazines to their full capacity, offers close to 6.8 SPC performance in a smaller package (when fired in a 16″ barrel it pushes 90 gr, 100 gr and 110 gr projectiles to 2,700 fps, 2,600 fps and 2,500 fps respectively) and all you need to convert an AR-15 to this caliber is to change the barrel. As you can see, this cartridge is perfect for the AR platform, but aren’t we discussing an AK in this article? Yes, and that’s what makes it an interesting and challenging project. I asked Daniel if there was any specific reason his customer wanted a .277 Wolverine AK and he answered that primarily it’s the interest in the cartridge itself and the will to explore its capabilities in different platforms. This is the third .277 Wolverine AK built by Halcyon Defense to date with the two other rifles belonging to Daniel and Mark Kexel, the owner of Mad Dog Weapon Systems and designer of this cartridge.

Halcyon Defense .277 Wolverine Tantal Conversion (6)

The core of this conversion is the barrel change. As you might expect, there are no .277 Wolverine AK barrels readily available so Daniel had to make it himself. He used a .277 caliber rifled barrel blank with 1:7″ twist rate which he cut a .277 Wolverine chamber in and profiled to fit the Tantal trunnion and barrel hardware. The barrel has a standard AK manhole sized gas port, but as you can see in the photos, the gun is equipped with a KNS Precision adjustable piston which will allow tuning the gas system to cycle anything from lightest supersonic bullet loads to heavy subsonic ones both suppressed and unsuppressed. To make the cartridges stagger properly and feed reliably, they used 5.56x45mm AK magazines borrowed from the Polish Beryl rifle.

In order to fit the Beryl magazines, the sides of the Tantal receiver magazine well were ever so slightly enlarged.
It is interesting to note, that despite being designed for a larger rim (10mm rim diameter of 5.45x39mm vs 9.6mm rim of 5.56x45mm), the 5.4539 Tantal bolt and extractor work with the 5.56/223 case perfectly. However, the firing pin has been shortened a bit to have a proper protrusion for the 5.56/223 primers.
The left side fire mode selector on semi-auto Tantal rifles is non-functional and merely supports the right side safety lever. In order to retain the left side selector (for the sake of coolness), Daniel milled a slot in the scope rail.

What you get as a result of this conversion is a 6.8mm AK that should have a felt recoil somewhere inbetween the 7.62x39mm and 5.56x45mm and suitable for a variety of hunting applications as well as for self/home defense. One issue with such a rifle will be the availability of ammunition – it’ll be much harder to find .277 Wolverine ammo compared to your standard .223 Rem or .308 Win. But if you are into reloading, then it should be quite interesting to experiment with different loads and bullets especially considering that Starline offers .277 Wolverine brass.

Tell me in the comments section what do you think about this Halcyon Defense Tantal conversion and the .277 Wolverine cartridge in general.


Images by Halcyon Defense and Mag Dog Weapon Systems

Hrachya H
Hrachya H

Managing Editor Being a lifelong firearms enthusiast, Hrachya always enjoys studying the history and design of guns and ammunition. Should you need to contact him, feel free to shoot him a message at Hrachya@TheFirearmBlog.com

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