How We Test Our Ammunition
Every penetration and expansion number we publish comes from a bullet that was fired into a gel block, dug back out, measured and weighed. Here's what a test day looks like, and why each step is there.
It starts with a data sheet
Every test day gets its own sheet before the first shot. We write down the date, the start and end times, the temperature at the start and at the end, the cartridge and bullet, and for each test, the gun and the distance. Temperature is on there because ammo can run at different speeds on a cold morning and a hot afternoon. If it isn't written down, we can't explain a number later.
The gel
Our gel blocks are 10% ballistic gel from Clear Ballistics, calibrated by the maker to the FBI standard. Gel stands in for soft tissue. Calibration is what makes a result mean something: blocks made to the same standard let you compare one test day to another, and our numbers to anyone else's who tests the same way. The blocks are clear, so the whole wound track can be seen and photographed from the side.
The barriers
Bare gel shows how a bullet behaves when nothing is in the way. That's rarely how it goes in real life, so we also shoot through what a bullet is likely to hit first. We follow the FBI's barrier tests for this, and most shots are fired from 10 feet, the FBI's standard distance. On a typical test day that means:
Bare gel
Denim over the block, the way heavy clothing would be
Drywall
Drywall and a wood stud
A windshield, set at an angle the way it sits in a car, with the block 18 inches behind the glass
The FBI's full protocol adds sheet steel and plywood. The VX9 has been through all of it, and the results are in our post on what barrier-blind means.
Speed
We measure speed with a chronograph. A hollow point needs speed to open, and barrel length changes speed, so a penetration number without the gun and the speed behind it doesn't tell you much. When we publish a speed, we name the gun it came from: the VX9 runs about 1,270 fps from a Glock 17, measured 15 feet from the muzzle.
Three measurements on every bullet we recover
After the shot, we recover the bullet and measure three things.
Penetration is how far the bullet went into the block, measured with a tape from the front face. The FBI looks for 12 to 18 inches: deep enough to reach vital organs from an awkward angle, without carrying on through the target.
Expansion is how wide the bullet opened, measured across its widest point. A wider bullet makes a wider wound and slows down inside the target instead of passing through it.
Retained weight is what the recovered bullet weighs on a scale, compared to its weight before it was fired. Any weight that's missing is metal that broke off. Those pieces stop pushing the bullet forward, and they keep moving on their own. For a solid copper bullet whose petals are meant to stay attached, this is the number that shows whether the design held.
Side by side
When we demo for an agency, we run their current duty ammo through the same tests next to ours: same gun, same blocks, same barriers. They leave with both sets of numbers. For rifle accuracy we shoot blind. The shooter doesn't know which ammo is in the magazine, a second person swaps magazines between groups, and the groups are shot within five minutes of each other so barrel heat doesn't skew the result.
Checked from the outside
Our own testing is where we learn. Outside testing is how we check ourselves. The VX9 has been through the full FBI protocol: bare gel, heavy clothing, steel, wallboard, plywood and auto glass. Out of a Glock 17 it averaged about 16 inches of penetration, inside the FBI's 12 to 18 inch window. It kept 99.7% of its weight and expanded every time.
If you're with an agency or buying for one, the full test data is available on request.
Comments