Technical notes
GJB4300A-2012 and why fragment testing is a separate question
Buyers who come to us from a military rather than a police programme usually ask about fragments before they ask about handgun rounds. GJB4300A-2012 is the standard that question sits under, and V50 rather than a pass or fail level is the number it produces.
What the standard covers
GJB4300A-2012 is the Chinese national military standard covering requirements and test methods for military body armor. Alongside the handgun and rifle threats a police standard would recognise, it addresses fragment protection, which is the dominant threat in most military scenarios: shell, grenade and IED fragments rather than aimed shots. That difference in threat drives a different test method, and a different kind of result.
Fragments are tested with a simulated projectile
You cannot test against real fragments, because no two are alike in shape, mass or tumble. Fragment testing therefore uses a fragment simulating projectile, or FSP: a standardised steel projectile of defined mass and geometry, fired at controlled velocity so results are comparable between samples and between laboratories. The 17-grain FSP, which is about 1.1 grams, is the size most commonly quoted for soft armor materials, and it is the one our own figures use.
Because the projectile is standardised, the interesting variable becomes velocity: not whether the material stops one particular shot, but at what speed it stops roughly half of them. That is V50, and it is the figure fragment testing is built to produce.
Our fragment figures
These V50 values are measured to GJB4300A-2012 or to STANAG 2920, at the areal density shown. Both fabrics are compared at the same 5.3 kg/m2, which is what makes the two numbers meaningful side by side.
Scroll the table sideways to see all columns.
- • A note on a unit that is often mistyped: the projectile is 17 grains, not 17 grams. A grain is roughly 0.0648 g, so 17 grains is about 1.1 g, which is the figure quoted alongside it.
What a fragment figure does not tell you
A V50 against fragments does not convert into a handgun protection level, and a handgun level does not predict fragment performance. They are different threats stopped by partly different mechanisms, measured by different methods, and reported in different units. If your specification names both, both have to be tested. If a supplier offers you a fragment number in place of a ballistic level, or the reverse, the thing to ask is which report actually exists.
The companion note on STANAG 2920 explains how a V50 figure is obtained and how to compare two of them fairly. Full specification tables for the fabrics named above are on the Soft Armor UD Fabric page.