PEFCO®: WHAT DIFFERENCES WITH DEFENCE BALLS

 

Various publications following the use of defense ball launchers(known as LBD in France) during the yellow vests demonstrations have caused more confusion than explained things.
 

We bring our point of view based on the conduct of several studies in terminal ballistics and experiments.

VOCABULARY

FIREARMS AND AMMUNITION:

Flash Ball: Is the brand of two-shot launcher manufactured by French company Verney Carron, it has been the precursor of kinetic launchers since 1992 in 44 caliber.

Caliber 44: exists in two versions of civilian weapons:

44 * 83 mm with a maximum energy of 150 Joules (category C)

44 * 83 SP with a maximum energy of 300 Joules (category B).

Due to its diameter, the probability of intra-orbital center impact is low, since the initial diameter of 44.4 mm exceeds 60 mm when it is expanded on impact if made of elastic materials of low hardness. (Shore 00 scale).

44*83 does exists anecdotally in riffled version – category A.(military weapons)

Caliber 40: 40mm * 56mm,  is the low speed version for individual grenade launcher (Category A – war weapons). The riffling impose an ogival projectile holded with a hard rear part for making it rotate. For that reason, the diameter of the head is generally smaller (usually 37mm) and is also not too deformable to prevent the head of the projectile tuching the barrel. Its impact diameter is usually close to 40mm.

LBD: Defensive Bullet Launcher is the name used by the French Ministry of the Interior during tenders for 40mm single-shot riffled launchers (category A), it has been in service in the French national police since 2008. In France, this acronym is repeated by the press and the public often undifferentiated with the name “Flash Ball” which is a weapon of a different category.

TECHNICAL TERMS

TRAJECTORY

Gyrostabilization: The rifled guns lead the projectiles in rotation and thus make it possible to stabilize it on his trajectory. This stabilization mode imposes a riffling grip ring of relatively hard and resilient material (thus deforming little on impact). It is therefore obviously more difficult to ensure non-lethality with projectiles of this type.

Arrow projectile: Smooth-bore weapons do not allow gyrostabilization; their trajectory can then be ensured either by a symmetrical aerodynamics (round ball), or by  aerodynamicaly stabilized shape (like an arrow); it is then an arrow projectile and no longer a bullet.

PARAMETERS

Energy: projectile mass at impact x impact velocity x impact velocity / 2

Force: mass x deceleration at impact (independent of the impact surface)

Constraint: force / impact surface (average value on the impact surface),

Gradient (force): is the rising slope of the force until its maximum. The stronger the gradient, the more the projectile causes damage with the risk of perforation or breakage.

Non lethality: this criterion is difficult to establish since the human constitution can vary by a factor of 5; that is to say, for the cranial thickness in particular some really have the head harder than others!

A Franco-German study published in 1991 established a maximum acceptable force of 5KN for a 40 mm diameter impact (MR35 PUNCH-MANURHIN rubber projectile) which gives a good margin of safety.

This value corresponds to an average constraint of less than approximately 5 kPa for head injuries.

MEASURES

Force wall: The quantification of the impact of a non-penetrating projectile is measured by the instantaneous force on a flat surface by French MOI and MOD. It allows to approach the instantaneous constraint by coupling it to a fast video. This tool is used experimentally by the technical services. However, it is not yet part of the official criteria for the classification and selection of non-lethal projectiles for administrations.
 

Hardness: it is usually expressed in Shore A for elastomers. For example, for a 40 Shore rubber foam, its quasi-static hardness will be (40 x density) Shore A. Below 10 Shore A, it passes on the Shore 00 scale (very deformable materials) usually reserved for mask molding. facials for the cinema.

These values are quasi-static values that do not translate reality into dynamic impact. Some materials harden with speed (this is the case for rubber that can double to hardness equivalent to 50 m / s).

It is for these reasons that we studied the dynamic aspect in the choice of our materials and selected those which retain their properties (and low values: Scale 00) even at high impact speed.

A NEW CONCEPT OF CONTROLLED FORCE

PEFCO:  a crush controled effect projectile

Our patented process for PEFCO allows to apply a similar energy to that of other LBDs: between 100 and 160 Joules in MO version and soon 70 to 90 Joules in personal defense version (pending classification) while significantly reducing the damage product.

At energy equals the PEFCO® projectile:

         – reduces the impact stress (less than 5 KPa),

         – eliminates the lesional risks due to the impact of the pellet inherent to the 40mm caliber,

         – increases the perceived pain with an impact surface multiplied by more than two for a time 2 times longer,

         – avoids the rebound effect (all the energy is delivered).

BECAUSE OF ITS ARROW STRUCTURE AND THE CHOICE OF MATERIALS, THE PEFCO TERMINAL BALISTIC BEHAVIOR AND THE CONSTRAINT APPLIED AT DURING IMPACT ARE NOT DEPENDENT OF ITS SPEED.