There is a growing popularity for the short barreled AR and AK. One of the AK varients that has exploded in popularity is the AKS72U, also known as the Krinkov. While Krinkov is an incorrect term, it has become the popular name for these AKs. There are Russian and Bulgarian Krinkov kits and rifles available. Similar but different are the Yugo M92s and Romanian Dracos which are compariably sized but different models. You can get one in 7.62×39, 5.45×39, or 5.56 Nato.
I am not going to pull any punches, these guns suck.
The problem is neither that these rifles (or pistol versions) are AKs, nor the short barrel length but the lack practical usefulness of these rifles. Now don’t get me wrong, if you want one as a fun gun, get it. But please don’t consider buying something like this for home defense, zombie apocalypse, Terminator uprising, etc.
Why are these rifles not practical? Several reasons including sight radius, size, weight. Let me use the AKS74U (or my SLR106UR) as an example.
Sight Radius: My AK has a sight radius shorter then some pistols. Not just are the sights close, they are hard to use. Now this can be negated by optic, but that is additional cost, and if you mount an optic on the side rail you can not fold the stock.
Size: Often the appeal of the Krinkov type AK is how very small it is. However for any sort of practical firing you will need to stock unfolded. With the stock extended, the overall length of the rifle is about 29 inches. That is almost identical to a M4 with the stock collapsed. That M4 with its stock collapsed has nearly twice the sight radius and twice the barrel length. Not to mention a good bit easier to shoot accurately. The Krinkov small size is only helpful for storage, not for shooting.
Weight: While the Krinkov is small, it is not light. A stock rifle is about 6 pounds. To compare it to the M4 again, is similar weight to a M4 with iron sights and plastic handguard. Not to mention that this AK starts off weighing almost as much as a larger rifle, it is far harder to mount any sort of useful accessories like optics and lights to it.
Ergonomics: The AK isn’t know for its ergonomics. However the Krinkov gets worse. Aside from the previously mentioned short sight radius, the handguards on these shortened AK get very hot, very fast. Much faster then on a standard length AK. Should you decided to run something like an Ultimak optics rail on a Krinkov, you may find your self burning your fingers should you not bring gloves. The stockless pistol versions of these rifles are heavy enough to make shooting them like a pistol awkward.
The worst for last, lack of modularity. Now normally this would be a non-issue. However if you compare the SBR’d AK to its competition, the SBR AR15, the AR15 is by far the better choice. Should you buy or build a Krinkov, what you have is what you are stuck with. A SBR AR15 can easily be modified for different calibres, barrel lengths, optics, etc. The short AK, even with its side rail and optional quad rail, lacks most of the flexibility a short AR has.
The main advantage of something like the Krinkov is that you can fold the stock (for storage, use in a vehicle, transportation, jumping, etc). However as soon as you unfold that stock, you are just left with an inferior rifle.
Should you choose to run something like this as your primary weapon, here are a few suggestions. I would recommend employing the weapon system much like how you would have employed a SMG. If using a left side folding stocked AK, get a railed dust cover or handguard to mount your optic on so it wont interfere with folding the stock. Have a good sling. Consider having a smaller mag (like a 20 rounder) for when you are concealing or storing the rifle. Make sure to pick ammo that will perform well with the reduced velocity from your rifle. Wear good ear protection due to the increase in flash and blast from the short barrel. Have fun.