#Api

After a temporary pause in producing video content, Royal Nonesuch is back. This YouTube channel is known for the variety of homemade gun projects. Not only he is back but also plans to start even more entertaining projects. He also applied for an FFL and SOT which will allow him to expand the range of weapons and mechanisms he can experiment with. Among his first new project is a gun utilizing an advanced primer ignition (API) mechanism with an extended chamber. Let’s see how the host of the channel describes his project.

Being a defense show rather than a firearms industry show, there are a bunch of interesting products to see at AUSA that one might not get a peek at elsewhere. An example of this kind of product is the Modular Interlocking Ballistic Barriers from KF Armory. These barriers are made of a solid proprietary rubber-like material, can absorb impacts up to .50 cal (for the variant rated for that round), and can be assembled into walls and structures in very little time.

It’s natural for a manufacturer to want to portray their product in the best possible light. But when the capabilities of your product are technical in nature, it can be tempting to advertise in such a way that less informed consumers might get the wrong idea. AR500Armor makes some very tough steel armor at a reasonable price. Their product is quite solid, really. But their enthusiastic marketing has moved into an area that is frankly misleading. They recently posted a video to their Facebook page that features their level III+ plate being hit by 5.56mm “API”. So far as I am aware, there has never been any “real” armor piercing incendiary 5.56mm issued by any military. When I asked them what the nomenclature of the ammunition was, they deleted my post and blocked me from further comment. When several other users pressed them, they eventually admitted that it was actually a  commercial offering. You might fairly inquire “So what?”. Why would it matter? Because the velocity recorded in their test was only 2,700 fps and the manufacturer of the ammo says that the penetrator is just “an M855 style penetrator”. M855 is easily stopped by all level III steel armor at substantially higher velocity than that seen in this test so the ammunition cannot be considered to be armor piercing either by military designation or by any stretch of the imagination. It is quite literally just a label applied by the ammo maker.  AR500Armor’s III+ plate actually is a very tough plate and has been shown in independent testing to stop actual armor piercing bullets from a 7.62x51mm rifle. Real AP ammo in 5.56mm would have no trouble defeating this plate, though. M995 would slice through like butter. M995 is rare as unicorn farts so it is unlikely that we will see any testing of it, but even the Army’s standard 5.56mm ball cut through their III+ plate so it’s likely that true 5.56mm AP would get through.  To be clear, AR500Armor hasn’t technically lied and they really do make a solid product, but this video seems to be intended to imply to viewers that their level III+ plate is able to stop all 5.56mm ammunition or even that it is able to stop armor piercing 5.56mm. That is most definitely not the case, which is unfortunate, because their III+ plate is otherwise a great plate.

Previously in TFB’s series on weapon operating mechanisms, we examined both the closed-bolt blowback system and the open-bolt API blowback system, two very close relatives that share a common feature: Closure of the breech through the inertia of the breechblock mass alone. What this means for small arms designers is that they must engineer a system where the breechblock is large enough to have sufficient mass, while having enough room to reciprocate the distance necessary for reliable ejection and feeding. In a standard submachine gun design using the API blowback system, for example, the breechblock is configured behind the breech end of the barrel, so that it can reciprocate. This is an easy design to engineer, and can be made simply and easily.

The first entry in our coverage of automatic weapon operating mechanisms will be the humble straight blowback method. Conceptually simple, it is one of the most common systems, being applied almost universally to .22 caliber rimfire autoloaders the world over, as well as being very commonly applied to budget centerfire handgun and rifle designs.

The subject of armor penetration previously was largely confined to the realm of big bore rifles or cannons intended to tackle tanks and other kinds of armored vehicles, but as the popularity of steel and composite body armor increases, it has become more and more relevant to the subject of small arms. It may be tempting to pull contextless data from different sources, and present them as being comparable, but in most cases this is a mistake. Unfortunately, quoting armor penetration numbers from two different countries or organizations is not a good way to compare the capabilities of rounds against one another, as I will explain.