Our investigation revealed that our vendor supplied middle rings which, although virtually identical dimensionally, were machined instead of forged, and therefore not as strong. Visually, the two types may not be reliably distinguishable from each other.
Tensile testing shows the forged rings to be more than twice as strong as the machined version.
Tests conducted on RW-2 rings purchased recently from a different vendor for test purposes concluded that they were also machined. At this time we are actively seeking a satisfactory ring to replace the machined ring. We will issue a service bulletin when more complete information is available.