A long time ago in a galaxy (and war zone) far, far away, a contact smiled and pressed a handful of rounds into my hand. “Here, take these. The guy I took them from doesn’t need them anymore,” he explained. Looking them over, it was a typical 9mm copper-washed steel case, but instead of a plain-vanilla 115-grain jacketed FMJ bullet, these were loaded with something altogether different.
For years, the Russians have been upgrading the performance of their 9mm handguns and subguns by feeding them armor-piercing ammunition. In 9×19 Luger, these have the designation of 7N21 and 7N31, the main distinction between the two being the weight of their projectiles.
According to published reference material, the former has a bullet weight of 5.4 grams, or 82 grains, while 7N31 is a comparative featherweight at 4.1 grams or 64 grains. Both are loaded into the +P+ range and zip right along at claimed velocities of 1,500 and 1,950 fps, respectively, when fired from a handgun.
Both projectiles are designed to shed their jackets when encountering significant resistance, leaving the hardened steel core to penetrate whatever substrate they encounter. In the case of 7N21, there’s a polyethylene sleeve between the core and jacket, presumably to aid the separation process.
In addition to the 9×19 rounds, there’s also a 9×21 cartridge designed for the SR1 Vector pistol and SR2 Veresk subgun fielded by the FSB. Designated 7N29, it slings a 103-grain bullet at 1,350 fps, also using a polyethylene sleeve.
Funnily enough, they’re almost never on the shelves at the local Sportsman’s Warehouse, so with the dearth of information in the West regarding the performance of these rounds, we decided to give them a closer look.
The copper-washed steel case of the sample rounds is almost indistinguishable from the typical Wolf 9mm Tula ball that’s currently sanctioned by the Biden administration, but in this case, it had no headstamp. It’s loaded with a very fine ball powder that looks like dark sand, and both the case mouth and primer annulus is sealed with red lacquer.
Bullet construction follows that of the 7N31, with a flat-based steel jacket wrapped around a hardened steel penetrator, which protrudes from the tip. Sectioning the bullet reveals a thin layer of lead between the jacket and core, effectively gluing the two together. It wasn’t until we placed it on the scale that we noticed something unusual.
Rather than the 82-grain weight we were expecting from the 7N31 ammo, these tipped the scale at an average of 106 grains, +/- 1.4 grains. Therefore, it would seem that in this loading, the Russian manufacturer substituted lead for polyethylene, bringing the weight of a 7N21 bullet up to around that of 9×21 Gyruza in their 9×19 round. As far as we know, no one in the West has tested it against armor.
Why the decision was made to substitute the heavier bullet is open to debate. The 7N21 and 7N31 largely rely on speed to defeat armor, but because of their poor sectional density and ballistic coefficients, they shed velocity quickly. It could be that the maker is attempting to achieve greater performance at distance through the use of a heavier bullet, but without knowing who made it, we’re at a loss as to who to ask.
Even if we did, it’s doubtful we’d get a reply, so we bounced the idea off of noted AP expert Howard Kent, CEO of Armor Development Group. “They’ve probably added mass in order to improve performance against ceramic armor,” said Kent. “The original bullet was designed to defeat steel, which skews the mass/speed formula toward velocity.”
So how does it perform? We’re glad you asked.
Since we were already in a war zone, it was easy to conduct a test. We set up a Level III Special Threat plate against a soft backer and shot it with the new round. The plate is rated to stop rifle-launched M855 rounds with their comparatively light steel penetrator, so we were curious to see what the effect, if any, was from a much slower projectile.
Our first impact was an edge hit, as ceramic armor tends to fail when struck toward its unsupported extremities, while the second center punched the plate. Both bullets were stopped by the armor, with the ceramic doing its job of deforming the steel penetrators enough for them to be caught by the aramid backer. Backface deformation was measured at 9mm.
We have no doubt that soft armor would be defeated by the 7N21 round, but for now, ceramics are resistant to the newer Russian ammunition.
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