FABRL Von Karman Bullets?
Perfect!
FABRL = Future Ammunition for Burst Rifle Launch.
This was a Frankford Arsenal program that ran from 1971-73 to study high L/D ratio projectiles with very low weight. There were a large number of projectiles whose designed centered around a composite cored bullet (steel, plastic, epoxy, tungsten, uranium, aluminum) with a weight of around 37 grains and a muzzle velocity of ca. 3,800 fps. Because of the ballistic efficiency a smaller powder charge can be used, and thus the shorter 38mm case.
This picture shows some of the variations produced:
From left to right:
5.56 x 38 Pressure Test
5.56 x 38 Sectioned showing a typical AR-2 projectile with a steel and plastic core. Within the case is a silicone insert called an FIE (Flexible Internal Element). This was a feature used in the development of the aluminum case to prevent burn-through – and was also used in the 6 x 49 aluminum cased SAW round.
The next 4 rounds are in 5.56 x 45 and predate the 38mm case rounds. These are ballistic test rounds that were single loaded when fired because they will not fit in an AR magazine like the 38mm case round will. Also featured are some projectiles of different designs. Of particular note is the frangible projectile formed around a steel rod. The rod has not yet been trimmed.
Fumer projectiles were also developed. Fumers (aka base bleed) function like a tracer round, in that there is a chemical element that burns, but instead of producing visible light, they function only to generate gas which reduces the base drag.
Paul
